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{{Short description|Airborne, submerged, and transmedium phenomena considered unusual and unidentified}}
{{Redirect|UFO|other uses|Unidentified flying object (disambiguation)|and|UFO (disambiguation)}}
{{Distinguish|Flying saucer}}
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{{Use mdy dates|date=May 2023}}
{{More citations needed|date=April 2024}}
[[File:Gimbal The First Official UAP Footage from the USG for Public Release.webm|thumb|330x330px|"GIMBAL" [[Pentagon UFO videos|Pentagon UFO video]], January 2015]]
An '''unidentified flying object''' ('''UFO'''), or '''unidentified anomalous phenomenon'''{{efn|group=lower-alpha|Also known as an '''unidentified aerial phenomena'''.<ref>{{Cite web |title=UAP FAQs – NASA Unidentified Anomalous Phenomena Study Frequently Asked Questions |url=https://science.nasa.gov/uap/faqs/ |access-date=January 30, 2024 |website=[[NASA]] |language=en}}</ref>}} ('''UAP'''), is any perceived airborne, submerged or transmedium phenomenon that cannot be immediately identified or explained.<ref>{{Cite web |title=50 U.S. Code § 3373 - Establishment of All-domain Anomaly Resolution Office |url=https://www.law.cornell.edu/uscode/text/50/3373 |access-date=2024-03-21 |website=LII / Legal Information Institute |language=en}}</ref> Upon investigation, most UAPs are [[Identification studies of UFOs|identified]] as known objects or atmospheric phenomena, while a small number remain unexplained.

While unusual sightings have been reported in the sky throughout history, UFOs became culturally prominent after [[World War II]], escalating during the [[Space Age]]. Studies and investigations into UFO reports conducted by governments (such as [[Project Blue Book]] in the United States and [[Project Condign]] in the United Kingdom), as well as by organisations and individuals have occurred over the years without confirmation of the fantastical claims of believers. The [[Federal government of the United States|U.S. government]] currently has two entities dedicated to UAP (or UFO) data collection and analysis: [[NASA's UAP independent study team]] and the [[All-domain Anomaly Resolution Office]].

Scientists and skeptic organizations such as the [[Committee for Skeptical Inquiry]] have provided prosaic explanations for UFOs, namely that they are caused by natural phenomena, human technology, delusions, and hoaxes. Small but vocal groups of [[ufologists]] favour unconventional or [[pseudoscience|pseudoscientific]] hypotheses, often claiming that UFOs are evidence of [[Extraterrestrial hypothesis|extraterrestrial intelligence]], [[Cryptoterrestrial hypothesis|technologically advanced cryptids]], [[Demon|demons]], [[Interdimensional UFO hypothesis|interdimensional contact]] or [[Time-traveller UFO hypothesis|future time travelers]], but even after decades of promotion of such ideas by believers and in popular media, [[Sagan standard|the kind of evidence required to solidly support such claims]] has not been forthcoming. Beliefs surrounding UFOs have inspired parts of [[UFO religion|new religions]] even as social scientists have identified the ongoing interest and storytelling surrounding UFOs as a modern example of [[folklore]] and [[mythology]] understandable with [[Psychosocial UFO hypothesis|psychosocial explanations]].

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==History==
{{Ufo}}
===Early history before the 20th century===
{{More citations|section|date=January 2024}}
People have always observed the sky and have sometimes seen what, to some, appeared to be unusual sights including phenomena as varied as [[comet]]s, bright [[meteors]], one or more of the [[Classical planet|five planets that can be readily seen with the naked eye]], [[Conjunction (astronomy)|planetary conjunctions]], and atmospheric [[Optical phenomenon|optical phenomena]] such as [[sun dog|parhelia]] and [[lenticular cloud]]s.{{Citation needed|reason=secondary sources needed connecting any of this to UFO history|date=August 2023}} One particularly famous example is [[Halley's Comet]]: first recorded by Chinese astronomers in 240 BC and possibly as early as 467 BC as a strange and unknown "guest light" in the sky.<ref>{{cite web |url= https://www.wired.com/2011/03/0330ancient-chinese-see-halleys-comet/|title= March 30, 240 B.C.: Comet Cometh to Cathay|author= |date= March 30, 2011|publisher= Wired|accessdate=June 23, 2024}}</ref> As a bright comet that visits the inner solar system every 76 years, it was often identified as a unique isolated event in ancient historical documents whose authors were unaware that it was a repeating phenomenon.{{Citation needed|reason=missing source for facts or claim|date=August 2023}} Such accounts in history often were treated as [[supernatural]] portents, [[angel]]s, or other religious [[omen]]s.{{Citation needed|reason=source needed for claim and for connection to UFO history|date=August 2023}} While UFO enthusiasts have sometimes commented on the narrative similarities between certain religious symbols in medieval paintings and UFO reports,<ref>{{cite web |url=http://www.americanchronicle.com/articles/16589 |title=Do UFOs Exist in the History of Arts? |last=Giordano |first=Daniela |date=November 13, 2006 |work=American Chronicle |publisher=Ultio, LLC |archive-url=https://web.archive.org/web/20120819213933/http://www.americanchronicle.com/articles/view/16589 |archive-date=August 19, 2012 |access-date=September 6, 2013}}</ref> the canonical and symbolic character of such images is documented by art historians placing more conventional religious interpretations on such images.<ref>{{cite journal |last=Cuoghi |first=Diego |date=2004 |title=The Art of Imagining UFOs |journal=[[Skeptic (U.S. magazine)|Skeptic]] |volume=11 |issue=1 |publisher=[[The Skeptics Society]] |url=http://www.skeptic.com/the_magazine/archives/vol11n01.html |access-date=September 6, 2013 |archive-date=October 3, 2012 |archive-url=https://web.archive.org/web/20121003170149/http://www.skeptic.com/the_magazine/archives/vol11n01.html |url-status=live }}</ref>

Some examples of pre-contemporary reports about unusual aerial phenomena include:
* [[Julius Obsequens]] was a [[Ancient Rome|Roman]] writer who is believed to have lived in the middle of the fourth century AD. The only work associated with his name is the ''Liber de prodigiis'' (Book of Prodigies), completely extracted from an epitome, or abridgment, written by [[Livy]]; ''De prodigiis'' was constructed as an account of the wonders and portents that occurred in [[Rome]] between 249 and 12 BCE. An aspect of Obsequens' work that has inspired excitement in some UFO enthusiasts is that he makes reference to things moving through the sky. The descriptions provided bear resemblance to observations of [[meteor showers]]. Obsequens was also writing some 400 years after the events he described, thus the text is not an eyewitness account. No corroboration with those amazing sights of old with contemporary observations was mentioned in that work.<ref>Julio Obsecuente, ''Libro de los Prodigios (restituido a su integridad, en beneficio de la Historia, por Conrado Licóstenes)'', ed. Ana Moure Casas (Madrid: Ediciones Clásicas, 1990)</ref><ref>Giulio Ossequente, ''Il Libro dei prodigi'', ed. Solas Boncompagni (Rome: Edizioni Mediterranee, 1992)</ref>
* [[Shen Kuo]] (1031–1095), a [[Song Dynasty|Song Chinese]] government [[Scholar-bureaucrat|scholar-official]] and prolific polymath inventor, wrote a vivid passage in his ''[[Dream Pool Essays]]'' (1088) about an unidentified flying object. He recorded the testimony of eyewitnesses in 11th-century [[Anhui]] and [[Jiangsu]] (especially in the city of [[Yangzhou]]), who stated that a flying object with opening doors would shine a blinding light from its interior (from an object shaped like a pearl) that would cast shadows from trees for ten [[Li (unit)|miles]] in radius, and was able to take off at tremendous speeds.<ref>Dong, Paul. (2000). ''China's Major Mysteries: Paranormal Phenomena and the Unexplained in the People's Republic''. San Francisco: China Books and Periodicals, Inc. ISBN 0-8351-2676-5. Pages 69–71.</ref> [[File:Basilea1566.jpg|thumb|220px|The celestial phenomenon over Basel in 1566.]]
* A woodcut by Hans Glaser that appeared in a broadsheet in 1561 has been featured in popular culture as the [[1561 celestial phenomenon over Nuremberg|"celestial phenomenon over Nuremberg"]] and connected to various [[ancient astronaut]] claims.<ref name="Vallee">{{cite book | url=https://books.google.com/books?id=XINLC2ubHqwC&pg=PT71 | title=Wonders in the Sky: Unexplained Aerial Objects from Antiquity to Modern Times | publisher=Tarcher |author1=Vallee, Jacques |author2=Aubeck, Chris | year=2010 | isbn=978-1585428205}}</ref> Skeptic and debunker [[Jason Colavito]] argues that the woodcut is "a secondhand depiction of a particularly gaudy sundog", a known [[Sun dog|atmospheric optical phenomenon]].<ref name=Colavito-121212>{{cite web | url=http://www.jasoncolavito.com/1/post/2012/12/the-ufo-battle-over-nuremburg.html | title=The UFO Battle over Nuremburg | website=jasoncolavito.com | date=December 12, 2012 | access-date=July 12, 2013 | first=Jason | last=Colavito | author-link=Jason Colavito | archive-date=December 20, 2012 | archive-url=https://web.archive.org/web/20121220012851/http://www.jasoncolavito.com/1/post/2012/12/the-ufo-battle-over-nuremburg.html | url-status=live }}</ref> A similar report comes from [[1566 celestial phenomenon over Basel|1566 over Basel]] and, indeed, in the 15th and 16th centuries, many leaflets wrote of "miracles" and "sky spectacles" which bear resemblance to natural phenomena which were only more fully characterized after the scientific revolution.<ref>{{Cite book |last=Borchert |url=https://books.google.com/books?id=rPRTzgEACAAJ |title=The book of miracles: Facsimile of the Augsburg manuscript from the Collection of Mickey Cartin |date=2013 |publisher=TASCHEN |isbn=978-3-8365-4285-2 |language=de}}</ref>
* On January 25, 1878, the ''[[Denison, Texas|Denison]] Daily News'' printed an article in which John Martin, a local farmer, had reported seeing a large, dark, circular object resembling a balloon flying "at wonderful speed". Martin, according to the newspaper account, said it appeared to be about the size of a saucer from his perspective, one of the first uses of the word "saucer" in association with a UFO. At the time, [[Balloon (aeronautics)|ballooning]] was becoming an increasingly popular and sophisticated endeavor, and the first controlled-flights of such devices were occurring around that time.<ref>{{cite web |url=http://www.americanchronicle.com/articles/17732 |title=Before the Wright Brothers ... There Were UFOs |last=Booth |first=B J |work=American Chronicle |publisher=Ultio, LLC |date=December 8, 2008 |archive-url=https://web.archive.org/web/20120819213938/http://www.americanchronicle.com/articles/view/17732 |archive-date=August 19, 2012 |access-date=September 6, 2013}}</ref>
{{multiple image
| perrow            = 2
| align             = left
| total_width       = 340
| header            = UFO-like alleged sightings before the 20th century
| image1            = Himmelserscheinung über Nürnberg vom 14. April 1561.jpg
| caption1          = [[1561 celestial phenomenon over Nuremberg]] as printed in an illustrated news notice.
| image2            = Mystery airship SFCall Nov 22 1896.jpg
| caption2          = November 22, 1896 illustration of a "[[mystery airship]]" published in ''[[The San Francisco Call]]''
| image3            = Mystery airship SFCall Nov 29 1896.jpg
| caption3          = November 29, 1896 illustration of another "[[mystery airship]]" published in ''[[The San Francisco Call]]''
| image4            = Mystery airship The Saint Paul Globe (Minn) April 13 1897.jpg
| caption4          = "[[Mystery airship]]" illustrated in ''[[The St. Paul Globe]]'', April 13, 1897
}}
* From November 1896 to April 1897, United States newspapers carried numerous reports of "[[mystery airship]]s" that are reminiscent of modern UFO waves.{{sfn|Cohen|1981|p=1}} Scores of people even reported talking to the pilots. Some people feared that [[Thomas Edison]] had created an artificial star that could fly around the country. On April 16, 1897, a letter was found that purported to be an enciphered communication between an airship operator and Edison.{{sfn|Cohen|1981|p=86}} When asked his opinion of such reports, Edison said, "You can take it from me that it is a pure fake."{{sfn|Keel|1996|pp=29–31|ps=, stating date of April 22, 1897}} The coverage of Edison's denial marked the end of major newspaper coverage of the airships in this period.{{sfn|Cohen|1981|p=88}}

===20th century and after===
{{See also|Investigation of UFO reports by the United States government|UFO conspiracy theories}}

In the Pacific and European theatres during [[World War II]], round, glowing fireballs known as "[[foo fighter]]s" were reported by Allied and Axis pilots. Some explanations for these sightings included [[St. Elmo's fire]], the planet [[Venus]], [[Asphyxia|hallucinations from oxygen deprivation]], and German secret weapons (specifically [[V-2 rocket|rockets]]).<ref>{{cite magazine|date=January 15, 1945|title=Foo-Fighter|url=http://www.time.com/time/magazine/article/0,9171,775433,00.html|url-status=dead|magazine=[[Time (magazine)|Time]]|archive-url=https://web.archive.org/web/20080417042038/http://www.time.com/time/magazine/article/0,9171,775433,00.html|archive-date=April 17, 2008|access-date=May 16, 2013}}</ref> In 1946, more than 2,000 reports were collected, primarily by the Swedish military, of unidentified aerial objects over the Scandinavian nations, along with isolated reports from France, Portugal, Spain, Italy, and Greece. The objects were referred to as "Russian hail" (and later as "[[ghost rockets]]") because it was thought the mysterious objects were possibly Russian tests of captured German [[V-1 flying bomb|V1]] or [[V-2 rocket|V2]] [[rocket]]s, but most were identified as natural phenomena as meteors.<ref>[[#Swords & Powell|Swords & Powell 2012]], p. 63</ref>
{{multiple image
| perrow = 2
| align = left
| total_width = 380
| image_gap =7
| background color = mintcream
| header = Science fiction depictions of spacecraft similar to [[flying saucer]]s before the first widely-reported UFO sighting in 1947
| image1 = The War of the Worlds by Henrique Alvim Corrêa, original graphic 05.jpg
| caption1 =Illustration from 1903 by [[Henrique Alvim Corrêa]] showing the first Martian emerging from a cylinder that had fallen from the sky for an edition of ''[[The War of the Worlds]]'' by H. G. Wells.
| image2 = Le-chevalier-illusion-no-839-conrad.jpg
| caption2 = Cover of French pulp magazine ''Le Chevalier Illusion'' from December 29, 1912 portraying a flying machine spreading a toxic gas among the passengers and crew of a ship below
| image3 = ModernElectrics1912-02.jpg
| caption3 = A "space flyer" depicted on the February 1912 cover of ''[[Modern Electrics]]'' as an illustration for the science fiction story ''[[Ralph 124C 41+]]'' by [[Hugo Gernsback]]
| image4 = Science and Invention Feb 1922 pg912 - War of the Future.jpg
| caption4 = Illustration by [[Frank R. Paul]] from February 1922 in ''Science and Invention'' showing [[Nikola Tesla]]'s vision of warfare in the future with sea and air craft "controlled and directed" by radio waves

| image5 = Münchhausen Lands On Mars by Hugo Gernsback in Amazing Stories April 1928 page 39.jpg
| caption5 = Illustration for a story by [[Hugo Gernsback]] in pulp [[science fiction]] magazine ''Amazing Stories'' from April 1928 (originally published on 1915 with similar illustrations in ''[[The Electrical Experimenter]]'')

| image6 = Science Wonder Stories Nov 1929 - flying saucer.jpg
| caption6 = Depiction of a [[flying saucer]] by illustrator [[Frank R. Paul]] on the October 1929 issue of [[Hugo Gernsback]]'s pulp [[science fiction]] magazine ''[[Science Wonder Stories]]''

| image7 = Amazing stories quarterly 1930win.jpg
| caption7 =Cover of ''[[Amazing Stories]]'' winter 1930 issue depicting a disc-shaped spacecraft

 | image8 = Amazing Stories August 1946 back cover.png
| caption8 = Back cover of ''[[Amazing Stories]]'' illustrated by [[Frank R. Paul]] in August 1946 featuring many disc-shaped spacecraft (published about a year before the flying disc wave of 1947)
}}
Many scholars, especially those arguing for the [[Psychosocial UFO hypothesis#Science fiction aspects of the UFO mythos|psychosocial UFO hypothesis]], have noted that UFO characteristics reported after the first widely publicized modern sighting by [[Kenneth Arnold]] in 1947 resembled a host of science fiction tropes from earlier in the century.<ref>Jeffrey J. Kripal, ''Authors of the Impossible: The Paranormal and the Sacred'', University of Chicago Press, 2010, pp. 206–8.</ref><ref>Bertrand Meheust, ''Science Fiction et Soucoupes Volantes''  Mercure de France, 1978</ref><ref>Michel Monnerie, Le Naufrage des Extra-terrestres, Nouvelles Editions Rationalistes, 1979.</ref><ref>Michel Meurger, ''ALIEN ABDUCTION: L'enlèvement Extraterrestre de la Fiction à la croyance --  Scientifictions: la Revue de l'Imaginaire Scientifique; numero 1, volume 1''  Encrage, 1995 (in French)  253pp.</ref><ref>Michel Meurger, "Surgeons from Outside"  ''Fortean Studies'' # 3  (1996) pp. 308–21.</ref><ref>Jacques Vallee, ''Dimensions: A Casebook of Alien Contact Contemporary Books'', 1988, p. 167.</ref><ref>Martin S. Kottmeyer, ''Magonia'' #90; November 2005, pp. 3–15. "[http://magonia.haaan.com/2010/enginestoppers/ Engine Stoppers] {{webarchive|url=https://web.archive.org/web/20131001033541/http://magonia.haaan.com/2010/enginestoppers/ |date=2013-10-01 }}"</ref>

By most accounts, the [[1947 flying disc craze|popular UFO craze]] in the USA began with a media frenzy surrounding the reports on June 24, 1947, of a civilian pilot named [[Kenneth Arnold]] who described seeing "a group of bat-like aircraft flying in formation at high speeds" near [[Mount Rainier]] that he said were "moving like a saucer would if skipped across water" which led to headlines about "flying saucers" and "flying discs".<ref>{{cite book |last=Pasulka |first=D.W. |title=American Cosmic: UFOs, Religion, Technology |isbn=978-0190692889 |publisher=Oxford University Press |date=18 January 2019 |pages=237 |quote=the standard assumption that the UFO mythos was born in the year 1947}}</ref><ref name=Eghigian4August2021>{{cite web |url=https://www.bostonreview.net/articles/ufos-and-the-boundaries-of-science/ |title=UFOs and the Boundaries of Science |last=Eghigian |first=Greg |date=4 August 2021 |publisher=Boston Review |access-date=19 June 2023 |archive-url=https://web.archive.org/web/20230410030607/https://www.bostonreview.net/articles/ufos-and-the-boundaries-of-science/ |archive-date=10 April 2023}}</ref><ref>{{Cite news|last=Garber|first=Megan|title=The Man Who Introduced the World to Flying Saucers|newspaper=The Atlantic|url=https://www.theatlantic.com/technology/archive/2014/06/the-man-who-introduced-the-world-to-flying-saucers/372732/ |access-date=February 2, 2017|archive-date=November 11, 2020|archive-url=https://web.archive.org/web/20201111183726/https://www.theatlantic.com/technology/archive/2014/06/the-man-who-introduced-the-world-to-flying-saucers/372732/|url-status=live}}</ref><ref>{{cite web|title=Saturday Night Uforia Audioplex: Edward R. Murrow - The Case ForOf The Flying Saucer (April 7, 1950 broadcast)|url=http://www.saturdaynightuforia.com/audioplex/audioplexhtml/murrowcaseofflyingsaucer.html|access-date=February 2, 2017|website=www.saturdaynightuforia.com|archive-date=July 18, 2019|archive-url=https://web.archive.org/web/20190718182303/https://www.saturdaynightuforia.com/audioplex/audioplexhtml/murrowcaseofflyingsaucer.html|url-status=live}}</ref> Only weeks after Arnold's story was reported in 1947, [[Gallup, Inc.|Gallup]] published a poll asking people in the United States what the "flying saucers" might be. Already, 90% had heard of the new term. However, as reported by historian Greg Eghanian, "a majority either had no idea what they could be or thought that witnesses were mistaken" while "visitors from space were not initially among the options that anyone had in mind, and Gallup didn't even mention if anyone surveyed brought up aliens.<ref name=Eghigian4August2021 /><ref name=Eghigian2017>{{cite web |url=https://www.historians.org/research-and-publications/perspectives-on-history/march-2017/more-human-than-alien-researching-the-history-of-ufos |title=More Human Than Alien: Researvching the History of UFOs |last=Eghigian |first=Greg |date=14 March 2017 |publisher=Perspectives on History |access-date=8 July 2023 |archive-url=https://web.archive.org/web/20230621171135/https://www.historians.org/research-and-publications/perspectives-on-history/march-2017/more-human-than-alien-researching-the-history-of-ufos |archive-date=21 June 2023}}</ref><ref name=Eghigian5August2021>{{cite web |url=https://www.smithsonianmag.com/air-space-magazine/ufos-uapswhatever-we-call-them-why-do-we-assume-mysterious-flying-objects-are-extraterrestrial-180978374/ |title=UFOs, UAPs—Whatever We Call Them, Why Do We Assume Mysterious Flying Objects Are Extraterrestrial? |last=Eghigian |first=Greg |date=5 August 2021 |publisher=Smithsonian Magazine |access-date=8 July 2023 |archive-url=https://web.archive.org/web/20230611013718/https://www.smithsonianmag.com/air-space-magazine/ufos-uapswhatever-we-call-them-why-do-we-assume-mysterious-flying-objects-are-extraterrestrial-180978374/ |archive-date=11 June 2023}}</ref>
Within weeks, reports of flying saucer sightings became a daily occurrence<ref>{{Cite web|title=Flying saucers still evasive 70 years after pilot's report {{!}} The Spokesman-Review|url=https://www.spokesman.com/stories/2017/jun/25/flying-saucers-still-evasive-70-years-after-pilots/|access-date=2021-12-30|website=www.spokesman.com|archive-url=https://web.archive.org/web/20220812160716/https://www.spokesman.com/stories/2017/jun/25/flying-saucers-still-evasive-70-years-after-pilots/|archive-date=12 August 2022}}</ref> with one particularly famous example being the [[Roswell incident]] in 1947 where remnants of a downed [[observation balloon]] were recovered by a farmer and confiscated by military personnel.<ref>{{cite book |last=Olmsted |first=Kathryn S. |date=2009 |title=Real Enemies: Conspiracy Theories and American Democracy, World War I to 9/11 |location=Oxford, UK |publisher=Oxford University Press |page=184 |isbn=978-0199753956 |quote=The material recovered near Roswell was consistent with a balloon device and most likely from one of the MOGUL balloons that had not been previously recovered.}}</ref> UFO enthusiasts in the early 1950s started to organize local "saucer clubs" modeled after [[science fiction]] [[fan club]]s of the 1930s and 1940s, with some growing to national and international prominence within a decade.<ref name=Eghigian4August2021 /> In 1950, three influential books were published—[[Donald Keyhoe]]'s ''[[The Flying Saucers Are Real]]'', [[Frank Scully]]'s ''Behind the Flying Saucers'', and [[Gerald Heard]]'s ''The Riddle of the Flying Saucers''. Each guilelessly proposed that the [[extraterrestrial UFO hypothesis]] was the correct explanation and that the visits were in response to detonations of [[Nuclear weapon|atomic weapons]]. These books also introduced Americans to, as Eghanian puts it, "the crusading [[whistleblower]] dedicated to breaking the silence over the alien origins of unidentified flying objects".<ref name=Eghigian4August2021 /> Media accounts and speculation ran rampant in the U.S., especially in connection to the [[1952 Washington, D.C., UFO incident|1952 UFO scare in Washington, D.C.]] so that, by 1953, the intelligence officials ([[Robertson Panel]]) worried that "genuine incursions" by enemy aircraft "over U.S. territory could be lost in a maelstrom of kooky hallucination" of UFO reports.<ref name="Lewis-Kraus-30-4-21">{{cite magazine|last1=Lewis-Kraus|first1=Gideon|date=April 30, 2021|title=How the Pentagon Started Taking U.F.O.s Seriously|url=https://www.newyorker.com/magazine/2021/05/10/how-the-pentagon-started-taking-ufos-seriously|magazine=The New Yorker magazine|archive-url=https://web.archive.org/web/20230623023008/https://www.newyorker.com/magazine/2021/05/10/how-the-pentagon-started-taking-ufos-seriously|archive-date=23 June 2023}}</ref> A Trendex survey in August 1957, ten years after the Arnold incident, reported that over 25% of the U.S. public "believed unidentified flying objects could be from outer space".<ref name=Eghigian4August2021 /> The cultural phenomenon showed up within some intellectual works such as the 1959 publication of ''Flying Saucers: A Modern Myth of Things Seen in the Sky'' by [[Carl Jung]], a Swiss psychiatrist and psychoanalyst who founded analytical psychology.<ref>{{cite book |last1=Jung |first1=Carl |translator-last1=Hull |translator-first1=R. F. C. |title=Flying Saucers: A Modern Myth of Things Seen in the Skies |language=en |publication-place=Broadway House, London |publisher=Routledge & Kegan Paul |publication-date=1959 }}</ref>

Starting in 1947, the U.S. Air Force began to record and investigated UFO reports with [[Project Sign]] looking into "more than 250 cases" from 1947 to 1949. It was replaced by [[Project Grudge]] up through 1951.<ref name=Eghigian19December2017>{{cite web |url=https://www.smithsonianmag.com/air-space-magazine/secret-government-program-track-ufos-its-not-first-180967597/ |title=That Secret Government Program to Track UFOs? It's Not the First |last=Eghigian |first=Greg |date=19 December 2017 |publisher=Smithsonian Magazine |access-date=8 July 2023 |archive-url=https://web.archive.org/web/20230606110707/https://www.smithsonianmag.com/air-space-magazine/secret-government-program-track-ufos-its-not-first-180967597/ |archive-date=6 June 2023 }}</ref> In the third U.S. Air Force program, from March 1952 to its termination in December 1969,<ref>Michael D. Swords; "UFOs, the Military, and the Early Cold War Era", pp. 82–121 in "UFOs and Abductions: Challenging the Borders of Knowledge" David M. Jacobs, editor; 2000, University Press of Kansas, {{ISBN|0700610324}}; p. 103.</ref> "the U.S. Air Force cataloged 12,618 sightings of UFOs as part of what is now known as [[Project Blue Book]]".<ref name="Mathis 6 July 2023">{{cite magazine |last1=Mathis |first1=Joel |date=6 July 2023 |title=What we know from decades of UFO government investigations |url=https://www.nationalgeographic.com/science/article/ufo-alien-spacecraft-investigation-timeline |magazine=National Geographic |archive-url=https://web.archive.org/web/20230708085036/https://www.nationalgeographic.com/science/article/ufo-alien-spacecraft-investigation-timeline |archive-date=8 July 2023}}</ref> In the late 1950s, public pressure mounted for a full declassification of all UFO records, but the CIA played an role in refusing to allow this.<ref>{{cite journal |last1=Haines |first1=Gerald K. |date=1997 |title=A Die-Hard Issue: CIA's Role in the Study of UFOs, 1947-90 |url=https://www.cia.gov/static/105bd8290b90de13ee136fecc9fe863f/cia-role-study-UFOs.pdf |journal=Studies in Intelligence |volume=1 |issue=1 |pages=67–84 |access-date=8 July 2023}}</ref> This sense was not universal in the CIA, however, as fellow [[National Investigations Committee On Aerial Phenomena|NICAP]] official [[Donald E. Keyhoe]] wrote that Vice Admiral [[Roscoe Hillenkoetter]], the first director of the CIA, "wanted public disclosure of UFO evidence".<ref>
{{cite book
 |first=Donald E.
 |last=Keyhoe
 |author-link=Donald E. Keyhoe
 |title=Aliens from space; the real story of unidentified flying objects
 |edition=1st
 |year=1973
 |publisher=[[Doubleday (publisher)|Doubleday]]
 |location=[[Garden City, New York]]
 |isbn=0-385-06751-8
 |url=https://archive.org/details/aliensfromspacer00keyh
 }}</ref> Official U.S. Air Force interest in UFO reports went on hiatus in 1969 after a study by the University of Colorado led by Edward U. Condon and known as the [[Condon Report]] concluded "that nothing has come from the study of UFOs in the past 21 years that has added to scientific knowledge" and that further time investigating UFO reports "cannot be justified".<ref name="Mathis 6 July 2023"/>
[[File:Keyhoe - The Flying Saucers Are Real, cover.jpg|thumb|180px|Cover of the 1953 book ''[[The Flying Saucers Are Real]]'' by [[Donald Keyhoe]]]]
[[File:Amazing Stories October 1957.jpg|thumb|180px|Cover of the pulp science fiction magazine ''[[Amazing Stories]]'' from October 1957]]
From the 1960s to 1990s, UFOs were part of American popular culture's obsession with the [[supernatural]] and [[paranormal]]. In 1961, the first [[alien abduction]] account was sensationalized when [[Barney and Betty Hill]] underwent [[hypnosis]] after seeing a UFO and reported [[Recovered-memory therapy|recovered memories]] of their experience that became ever more elaborate as the years went by.<ref>{{Cite news |date=October 23, 2004 |title=Betty Hill, 85, Figure in Alien Abduction Case, Dies |work=[[The New York Times]] (online) |url=https://www.nytimes.com/2004/10/23/us/betty-hill-85-figure-in-alien-abduction-case-dies.html |access-date=January 29, 2020}}</ref> In 1966, 5% of Americans reported to Gallup that "they had at some time seen something they thought was a 'flying saucer'", 96% said "they had heard or read about flying saucers", and 46% of these "thought they were 'something real' rather than just people's imagination".<ref>{{cite web |first=Lydia |last=Saad |title=Gallup Vault: Eyewitnesses to Flying Saucers |date=April 12, 2016 |url=https://news.gallup.com/vault/190592/gallup-vault-eyewitnesses-flying-saucers.aspx |access-date=8 July 2023 |publisher=Gallup |archive-date=23 May 2023 |archive-url=https://web.archive.org/web/20230523023423/https://news.gallup.com/vault/190592/gallup-vault-eyewitnesses-flying-saucers.aspx |url-status=live}}</ref> Responding to UFO enthusiasm, there have always been consistent yet less popular efforts made at [[debunking]] many of the claims,<ref name="Eghigian4August2021" /> and at times the media was enlisted including a 1966 TV special, "UFO: Friend, Foe or Fantasy?", in which [[Walter Cronkite]] "patiently" explained to viewers that UFOs were fantasy.<ref name="Lewis-Kraus-30-4-21" /> Cronkite enlisted [[Carl Sagan]] and [[J. Allen Hynek]], who told Cronkite, "To this time, there is no valid scientific proof that we have been visited by spaceships".<ref name="Kloor1">{{cite web |last1=Kloor |first1=Kieth |date=April 3, 2019 |title=UFOs Won't Go Away |url=https://issues.org/ufos-wont-go-away/ |url-status=live |archive-url=https://web.archive.org/web/20211108080728/https://issues.org/ufos-wont-go-away/ |archive-date=November 8, 2021 |access-date=November 8, 2021 |website=Issues. Vol. XXXV, No. 3, Spring 2019 |publisher=Arizona State University}}</ref>

Such attempts to disenchant the zeitgeist were not very successful at tamping down the mania. [[Keith Kloor]] notes that the "allure of flying saucers" remained popular with the public into the 1970s, spurring production of such sci-fi films, as ''[[Close Encounters of the Third Kind]]'' and ''[[Aliens (film)|Alien]]'', which "continued to stoke public fascination". Meanwhile, [[Leonard Nimoy]] narrated a popular occult and mystery TV series [[In Search of... (TV series)|''In Search of...'']] while daytime talk shows of [[Mike Douglas]], [[Merv Griffin]], and [[Phil Donahue]] featured interviews with alien abductees and people who credulously reported stories about UFOs .<ref name="Eghigian4August2021" /> In the 1980s and 1990s, UFO stories featured in such pulp "true crime" serials as ''[[Unsolved Mysteries]]''<ref>{{Cite journal |last1=Sparks |first1=Glenn G. |last2=Pellechia |first2=Marianne |last3=Irvine |first3=Chris |date=June 1998 |title=Does television news about UFOs affect viewers' UFO beliefs?: An experimental investigation |url=http://www.tandfonline.com/doi/abs/10.1080/01463379809370102 |journal=Communication Quarterly |language=en |volume=46 |issue=3 |pages=284–294 |doi=10.1080/01463379809370102 |issn=0146-3373}}</ref> while the 33 Volume [[Time Life|Time-Life]] series ''[[Mysteries of the Unknown]]'' which featured UFO stories sold some 700,000 copies.<ref>{{Cite web |date=2015-09-22 |title=The 1980s Book Series That Literally Claimed It Had To Be Read To Be Believed |url=http://www.atlasobscura.com/articles/the-1980s-book-series-that-literally-claimed-it-had-to-be-read-to-be-believed |access-date=2023-07-09 |website=Atlas Obscura |language=en}}</ref> Kloor writes that by the late 1990s, "other big UFO subthemes had been prominently introduced into pop culture, such as the abduction phenomenon and [[Conspiracy theory|government conspiracy narrative]], via best-selling books and, of course, ''[[The X-Files]]''".<ref name="Kloor1" />

Eghigian notes that, by this point, the UFO problem had become "far more interesting to ponder than to actually solve."<ref name=Eghigian4August2021 /> Interest was particularly fevered in the 1990s with the publicity surrounding the television broadcast of an ''[[Alien Autopsy (1995 film)|Alien autopsy]]'' video marketed as "real footage" but later admitted to be a staged "re-enactment".<ref name=Time>{{cite magazine|url=http://www.time.com/time/magazine/article/0,9171,983764-1,00.html|archive-url=https://web.archive.org/web/20091216074850/http://www.time.com/time/magazine/article/0,9171,983764-1,00.html|url-status=dead|archive-date=December 16, 2009|title=Autopsy or Fraud-topsy?|magazine=[[Time (magazine)|Time]]|author=Corliss, Richard|author-link=Corliss, Richard|date=November 27, 1995 | access-date=April 23, 2010}}</ref> Eghigian writes that "there had always been outlier abduction reports dating back to the '50s and '60s" but that in the '80s and '90s "the floodgates opened, and with them a new generation of UFO advocates". Leaders among them were the artist [[Budd Hopkins]], horror writer [[Whitley Strieber]], historian [[David M. Jacobs|David Jacobs]], and [[Harvard]] psychiatrist [[John E. Mack|John Mack]]. They all defended the "veracity of those claiming to have been kidnapped, examined, and experimented upon by beings from another world", writes Eghigian, as "new missionaries who simultaneously played the role of investigator, therapist, and advocate to their vulnerable charges".<ref name="Eghigian4August2021" /> Eghigian says that Mack "signaled both the culmination and end of the headiest days of alien abduction". When Mack began working with and publishing accounts of abductees — or "experiencers", as he called them — in the early 1990s, he brought a sense of legitimacy to "the study of extraterrestrial captivity". By the late 1990s, however, the Harvard Medical School initiated a review of his position which allowed him to retain tenure. However, after this review, as the review board chairman Arnold Relman later put it, Mack was "not taken seriously by his colleagues anymore". Claims of alien abduction have continued, but no other clinicians would continue to speak of them as real in any sense.<ref name="Eghigian4August2021" /> Nonetheless, these ideas persisted in popular opinion. According to a 1996 poll by ''[[Newsweek]]'', 20% of Americans believed that UFOs were more likely to be proof of alien life than to have a natural scientific explanation.<ref>{{cite web |url=https://today.yougov.com/topics/technology/articles-reports/2022/10/04/more-half-americans-believe-aliens-probably-exist |title=A growing share of Americans believe aliens are responsible for UFOs |last=Orth |first=Taylor |date=4 October 2022 |publisher=YouGov PLC (citing 1996 Newsweek poll) |access-date=19 June 2023 |archive-url=https://web.archive.org/web/20230531002256/https://today.yougov.com/topics/technology/articles-reports/2022/10/04/more-half-americans-believe-aliens-probably-exist |archive-date=31 May 2023 }}</ref>

In December 2017, a new round of media attention started when ''The New York Times'' broke the story of the secret [[Advanced Aviation Threat Identification Program]] that was funded from 2007 to 2012 with $22 million spent on the program.<ref name="NYT-20171216">{{cite news|url=https://www.nytimes.com/2017/12/16/us/politics/pentagon-program-ufo-harry-reid.html|title=Glowing Auras and 'Black Money': The Pentagon's Mysterious U.F.O. Program|last1=Cooper|first1=Helene|date=December 16, 2017|work=[[The New York Times]]|access-date=December 16, 2017|last2=Blumenthal|first2=Ralph|last3=Kean|first3=Leslie|archive-date=December 21, 2017|archive-url=https://web.archive.org/web/20171221235856/https://www.nytimes.com/2017/12/16/us/politics/pentagon-program-ufo-harry-reid.html|url-status=live}}</ref><ref name="NYT-20200514">{{cite news |last1=Blumenthal |first1=Ralph |last2=Kean |first2=Leslie |title=Navy Reports Describe Encounters With Unexplained Flying Objects - While some of the encounters have been reported publicly before, the Navy records are an official accounting of the incidents, including descriptions from the pilots of what they saw. |url=https://www.nytimes.com/2020/05/14/us/politics/navy-ufo-reports.html |date=May 14, 2020 |work=[[The New York Times]] |access-date=May 15, 2020 |archive-date=May 15, 2020 |archive-url=https://web.archive.org/web/20200515001002/https://www.nytimes.com/2020/05/14/us/politics/navy-ufo-reports.html |url-status=live }}</ref> Following this story, along with a serious of sensationalized [[Pentagon UFO videos]] leaked by members of the program who became convinced that UFOs were genuine mysteries worth investigating, there was an increase in mainstream attention to UFO stories. In July 2021, Harvard astronomer [[Avi Loeb]] announced the creation of his [[The Galileo Project|Galileo Project]] which intended to use high-tech astronomical equipment to seek evidence of extraterrestrial artifacts in space and possibly within Earth's atmosphere. This was followed closely by the publication of Loeb's book ''Extraterrestrial'', in which he argued that the first interstellar comet ever observed, [['Oumuamua]], might be an artificial light sail made by an alien civilization.<ref name="Eghigian4August2021" /> Two government sponsored programs, [[NASA's UAP independent study team]] and the [[All-domain Anomaly Resolution Office]] were charged in part by Congressional fiat to investigate UFO claims more fully,<ref>{{cite web |last1=Bock |first1=Michael |date=23 December 2022 |title=NASA to Set Up Independent Study on Unidentified Anomalous Phenomena |url=https://www.nasa.gov/feature/nasa-announces-unidentified-aerial-phenomena-study-team-members/ |archive-url=https://web.archive.org/web/20230610082955/https://www.nasa.gov/feature/nasa-announces-unidentified-aerial-phenomena-study-team-members/ |archive-date=10 June 2023 |access-date=23 June 2023 |website=NASA }}</ref><ref>[[Kathleen Hicks]] [https://media.defense.gov/2021/Nov/23/2002898596/-1/-1/0/ESTABLISHMENT-OF-THE-AIRBORNE-OBJECT-IDENTIFICATION-AND-MANAGEMENT-SYNCHRONIZATION-GROUP.PDF (23 November 2021) Establishment of the Airborne Object Identification and Management Synchronization Group]</ref><ref>{{cite web |last1=Vergun |first1=David |date=19 April 2023 |title=DOD Working to Better Understand, Resolve Anomalous Phenomena |url=https://www.defense.gov/News/News-Stories/Article/Article/3368109/dod-working-to-better-understand-resolve-anomalous-phenomena/ |archive-url=https://web.archive.org/web/20230613180406/https://www.defense.gov/News/News-Stories/Article/Article/3368109/dod-working-to-better-understand-resolve-anomalous-phenomena/ |archive-date=13 June 2023 |access-date=13 June 2023 |website=DOD News }}</ref> adopting the new moniker "unexplained aerial phenomenon" (UAP) to avoid associations with past [[sensationalism]].<ref>{{cite web |url=https://www.scientificamerican.com/article/bad-data-not-aliens-may-be-behind-ufo-surge-nasa-team-says/ |title=Bad Data, Not Aliens, May Be behind UFO Surge, NASA Team Says |last=Leonard |first=David |date=9 June 2023 |publisher=Scientific American |access-date=19 June 2023 |archive-url=https://web.archive.org/web/20230611131604/https://www.scientificamerican.com/article/bad-data-not-aliens-may-be-behind-ufo-surge-nasa-team-says/ |archive-date=11 June 2023 }}</ref>  On 17 May 2022, members of the [[United States House Intelligence Subcommittee on Counterterrorism, Counterintelligence and Counterproliferation]] held [[2022 United States Congress hearings on UFOs|congressional hearing]]s with top military officials to discuss military reports of UAPs.<ref>{{USCongRec|2022|D545|date=May 17, 2022}}</ref> It was the first public congressional hearing into UFO sightings in the US in over 50 years. Another Congressional hearing took place on July 26, 2023, featuring the [[David Grusch UFO whistleblower claims|whistleblower claims]] of former U.S. Air Force (USAF) officer and intelligence official David Grusch.<ref>{{Cite news |last=Merchant |first=Nomaan |date=26 July 2023 |title=Whistleblower tells Congress the US is concealing 'multi-decade' program that captures UFOs |newspaper=[[The Washington Post]] |url=https://www.washingtonpost.com/politics/2023/07/26/ufos-uaps-congress-whistleblower-spy-aliens/01081d9a-2bce-11ee-a948-a5b8a9b62d84_story.html |access-date=27 July 2023 |archive-date=26 July 2023 |archive-url=https://web.archive.org/web/20230726223917/https://www.washingtonpost.com/politics/2023/07/26/ufos-uaps-congress-whistleblower-spy-aliens/01081d9a-2bce-11ee-a948-a5b8a9b62d84_story.html |url-status=live }}</ref><ref>{{Cite news |last=De Avila |first=Joseph |date=26 July 2023 |title=UFOs Are a Common Sight, Former Military Official Tells Congress |work=[[The Wall Street Journal]] |url=https://www.wsj.com/articles/house-oversight-committee-congress-ufo-hearing-ceeceae6 |archive-date=27 July 2023 |archive-url=https://web.archive.org/web/20230727031909/https://www.wsj.com/articles/house-oversight-committee-congress-ufo-hearing-ceeceae6 |url-access=subscription}}</ref><ref>{{Cite news |last=Cooper |first=Helene |date=26 July 2023 |title=Lawmakers and Former Officials Press for Answers on U.F.O.s |work=[[The New York Times]] |url=https://www.nytimes.com/2023/07/26/us/politics/ufo-hearing.html |access-date=27 July 2023 |archive-date=27 July 2023 |archive-url=https://web.archive.org/web/20230727033839/https://www.nytimes.com/2023/07/26/us/politics/ufo-hearing.html |url-status=live }}</ref>

A Harris Poll in 2009 found that 32% of Americans "believe in UFOs".<ref>{{cite book |last=Pasulka |first=D.W. |title=American Cosmic: UFOs, Religion, Technology |isbn=978-0190692889 |publisher=Oxford University Press |date=18 January 2019 |pages=7 |quote=the standard assumption that the UFO mythos was born in the year 1947}}</ref> A ''[[National Geographic]]'' study in June 2012 found that 36% of Americans believe UFOs exist and that 10% thought that they had spotted one.<ref>{{cite web |url=https://abcnews.go.com/Technology/ufos-exist-americans-national-geographic-survey/story?id=16661311 |title=UFOs Exist, Say 36 Percent in National Geographic Survey |last=Harish |first=Alon |date=27 June 2012 |publisher=ABC News |access-date=19 June 2023 |archive-url=https://web.archive.org/web/20230609235400/https://abcnews.go.com/Technology/ufos-exist-americans-national-geographic-survey/story?id=16661311 |archive-date=9 June 2023 }}</ref> In June 2021 a [[Pew]] research poll found that 51% in the United States thought that UFOs reported by people in the military were likely to be evidence of intelligent life from beyond the Earth.<ref>{{cite web |url=https://www.pewresearch.org/short-reads/2021/06/30/most-americans-believe-in-intelligent-life-beyond-earth-few-see-ufos-as-a-major-national-security-threat/ |title=Most Americans believe in intelligent life beyond Earth; few see UFOs as a major national security threat |last1=Kennedy |first1=Courtney |last2=Lau |first2=Arnold |date=30 June 2021 |publisher=Pew |access-date=19 June 2023 |archive-url=https://web.archive.org/web/20230603161538/https://www.pewresearch.org/short-reads/2021/06/30/most-americans-believe-in-intelligent-life-beyond-earth-few-see-ufos-as-a-major-national-security-threat/ |archive-date=3 June 2023 }}</ref> In August 2021, [[Gallup, Inc.|Gallup]], with a question not specific to military reports, only found that 41% of adults believed some UFOs involve alien spacecraft from other planets. This Gallup poll showed 44% of men and 38% of women believed this. This average of 41% in 2021 was up from 33% in a 2019 Gallup poll with the same question. Gallup further found that college graduates went in 2019 from being the least likely educational group to believe this to being on par in 2021 with adults who have no college education.<ref>{{cite web |url=https://news.gallup.com/poll/353420/larger-minority-says-ufos-alien-spacecraft.aspx |title=Larger Minority in U.S. Says Some UFOs Are Alien Spacecraft |last=Saad |first=Lydia |date=20 August 2021 |publisher=Gallup |access-date=19 June 2023 |archive-url=https://web.archive.org/web/20230523014539/https://news.gallup.com/poll/353420/larger-minority-says-ufos-alien-spacecraft.aspx |archive-date=23 May 2023 }}</ref> An October 2022 poll by ''[[YouGov]]'' only found that 34% of Americans believe that UFOs are likely to involve alien life forms.<ref>{{cite web |url=https://today.yougov.com/topics/technology/articles-reports/2022/10/04/aliens-ufos-yougov-poll-september-9-12-2022 |title=Aliens and UFOs: YouGov Poll: September 9 - 12, 2022 |last=Linley |first=Sanders |date=4 October 2022 |publisher=YouGov PLC |access-date=19 June 2023 |archive-url=https://web.archive.org/web/20230425114950/https://today.yougov.com/topics/technology/articles-reports/2022/10/04/aliens-ufos-yougov-poll-september-9-12-2022 |archive-date=25 April 2023}}</ref>

Historian Greg Eghigian wrote in August 2021 that "over the last fifty years, the mutual antagonism between paranormal believers and skeptics has largely framed discussion about unidentified flying objects" and that "it often gets personal" with those taking seriously the prospect that UFOs are extraterrestrial in origin dismissing those who consider UFOs to be worth studying as "narrow-minded, biased, obstinate, and cruel" while the skeptics brushed off "devotees" as "naïve, ignorant, gullible, and downright dangerous". Such "mudslinging over convictions is certainly familiar to historians of religion, a domain of human existence marked by deep divisions over interpretations of belief", and science too has found itself engaged increasing amounts of "boundary work" (which is "asserting and reasserting the borders between legitimate and illegitimate scientific research and ideas, between what may and what may not refer to itself as science") with regard to UFO questions. Eghigian points out our current "stark divide did not happen overnight, and its roots lie in the postwar decades, in a series of events that—with their news coverage, grainy images, celebrity crusaders, exasperated skeptics, unsatisfying military statements, and accusations of a government cover-up—foreshadow our present moment".<ref name=Eghigian4August2021 />

UFOs have been taken up by religious studies scholars in various scholarly books.<ref>{{Cite book |last=Kripal |first=Jeffrey J. |url=http://dx.doi.org/10.7208/chicago/9780226453897.001.0001 |title=Authors of the Impossible |date=2010 |publisher=University of Chicago Press |doi=10.7208/chicago/9780226453897.001.0001 |isbn=978-0-226-45387-3}}</ref><ref>{{Cite journal |last=Davison |first=Andrew |date=2019-10-02 |title=Astrotheology: Science and Theology Meet Extraterrestrial Life |url=http://dx.doi.org/10.1080/14746700.2019.1670968 |journal=Theology and Science |volume=17 |issue=4 |pages=551–554 |doi=10.1080/14746700.2019.1670968 |s2cid=211965883 |issn=1474-6700}}</ref><ref>{{Cite journal |last=Cusack |first=Carole M. |date=2019 |title=D. W. Pasulka, American Cosmic: UFOs, Religion, Technology |url=http://dx.doi.org/10.5840/asrr201910263 |journal=Alternative Spirituality and Religion Review |volume=10 |issue=2 |pages=258–259 |doi=10.5840/asrr201910263 |s2cid=213855394 |issn=1946-0538}}</ref> Jeffrey Kripal, chair of the Department of Religion at [[Rice University]], has said that "both the material and the mental dimensions [of UFOs] are incredibly important to get a sense of the full picture".<ref>{{cite web |url=https://news.rice.edu/news/2021/jeffrey-kripal-how-think-about-ufo-phenomenon |title=Jeffrey Kripal on how to think about the UFO phenomenon |last=Shilcutt |first=Katharine |date=30 June 2021 |publisher=Rice University News and Media Relations Team |access-date=19 June 2023 |archive-url=https://web.archive.org/web/20230213224448/https://news.rice.edu/news/2021/jeffrey-kripal-how-think-about-ufo-phenomenon |archive-date=13 February 2023}}</ref> As Adrian Horton writes "from ''[[The X-Files]]'' to ''[[Men in Black (franchise)|Men in Black]]'', ''[[Close Encounters of the Third Kind]]'' to ''[[Star Wars]]'' to [[Marvel Cinematic Universe|Marvel]], [[Cinema of the United States|Hollywood]] has for decades provided an engrossing feedback loop for interest in the extraterrestrial: a reflection of our fears and capaciousness, whose ubiquitous popularity has in turn fueled more interest in UFOs as perennially compelling entertainment tropes not to be taken seriously". Horton observes that these "alien movies have generally reflected shifting cultural anxieties, from the existential terror of nuclear war to foreign enslavement to loss of bodily control". American entertainment has explored both "hostile aliens" as well as the "benevolent, world-expanding encounters" seen in films such as [[Steven Spielberg]]'s ''[[Close Encounters of the Third Kind]]'' and ''[[E.T. the Extra-Terrestrial]]''.<ref>{{cite web |url=https://www.theguardian.com/culture/2021/jun/25/how-pop-culture-has-shaped-our-understanding-of-aliens |title=How pop culture has shaped our understanding of alien |last=Shilcutt |first=Adrian |date=25 June 2021 |publisher=Guardian News |access-date=19 June 2023 |archive-url=https://web.archive.org/web/20230605002338/https://www.theguardian.com/culture/2021/jun/25/how-pop-culture-has-shaped-our-understanding-of-aliens |archive-date=5 June 2023 }}</ref> In her research on the relationship of media to UFO beliefs, [[Diana Walsh Pasulka]], a professor of philosophy and religion at the University of North Carolina, says that what is seen on a screen, "if it conforms to certain criteria, is interpreted as real, even if it is not real and even if one knows it is not real" and that "screen images embed themselves in one's brain and memories" in ways that "can determine how one views one's past and even determine one's future behaviors".<ref>{{cite book |last=Pasulka |first=D.W. |title=American Cosmic: UFOs, Religion, Technology |isbn=978-0190692889 |publisher=Oxford University Press |date=18 January 2019 |pages=82 |quote=the standard assumption that the UFO mythos was born in the year 1947}}</ref>
===Notable cases and incidents===
{{See also|List of reported UFO sightings}}

====Britain====
* The [[Rendlesham Forest incident]] was a series of reported sightings of unexplained lights near Rendlesham Forest in Suffolk, England in late December 1980 which became linked with claims of UFO landings.

====France====

The most notable cases of UFO sightings in France include:
* the [[Valensole UFO incident]] in 1965.
* the [[Trans-en-Provence Case]] in 1981.
[[File:Roswell Daily Record. July 8, 1947. RAAF Captures Flying Saucer On Ranch in Roswell Region. Full front page.jpg|thumb|A [[Roswell incident|Roswell]] Daily Record on July 8, 1947, reporting a UFO case]]

====United States====
* In the [[Kecksburg UFO incident]], Pennsylvania (1965), residents reported seeing an object crash in the area.
* In 1975, [[Travis Walton (UFO witness)|Travis Walton]] claimed to be abducted by aliens. The movie ''[[Fire in the Sky]]'' (1993) was based on this event, but greatly embellished the original account.
* The "[[Phoenix Lights]]" on March 13, 1997

====Astronomer reports====

The USAF's Project Blue Book files indicate that approximately 1% of all unknown reports<ref>{{cite web |url=http://www.cufos.org/BB_Unknowns.html |title=Comprehensive Catalog of 1,600 Project BLUE BOOK UFO Unknowns |date=October 2, 2009 |editor-last=Sparks |editor-first=Brad |website=CUFOS.org |publisher=Center for UFO Studies |location=Chicago |access-date=July 13, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130630035534/http://www.cufos.org/BB_Unknowns.html |archive-date=June 30, 2013  }}</ref> came from amateur and professional astronomers or other telescope users (such as missile trackers or surveyors). In 1952, astronomer J. Allen Hynek, then a consultant to Blue Book, conducted a small survey of 45 fellow professional astronomers. Five reported UFO sightings (about 11%). In the 1970s, astrophysicist [[Peter A. Sturrock]] conducted two large surveys of the AIAA and [[American Astronomical Society]] (AAS). About 5% of the members polled indicated that they had had UFO sightings.

Astronomer [[Clyde Tombaugh]], who saw six UFOs, including three green fireballs, supported the extraterrestrial hypothesis for UFOs and said scientists who dismissed it without study were "unscientific". Another astronomer, [[Lincoln LaPaz]], headed the United States Air Force's investigation into green fireballs and other UFO phenomena in New Mexico. LaPaz reported two personal sightings, of a green fireball and a disc. (Both Tombaugh and LaPaz were part of Hynek's 1952 survey.) Hynek took two photos through the window of a commercial airliner of a disc that seemed to keep pace with his aircraft.<ref>[[#Hynek 1972|Hynek 1972]], p. 52</ref>

Astronomer [[Andrew Fraknoi]] rejected the hypothesis that UFOs are extraterrestrial spacecraft and responded to the "onslaught of credulous coverage" in books, films and entertainment by teaching his students to apply critical thinking to such claims, advising them that "being a good scientist is not unlike being a good detective". According to Fraknoi, UFO reports "might at first seem mysterious", but "the more you investigate, the more likely you are to find that there is LESS to these stories than meets the eye".<ref name=Fraknoi>[[Andrew Fraknoi]], [http://adsabs.harvard.edu/full/2010ASPC..431..514F|''Science Education and Outreach: Forging a Path to the Future''] {{Webarchive|url=https://web.archive.org/web/20210526194646/http://adsabs.harvard.edu/full/2010ASPC..431..514F%7C%E2%80%98%E2%80%99Science |date=May 26, 2021 }}. Proceedings of a conference held September 12–16, 2009 in Millbrae, California, USA. Edited by Jonathan Barnes, Denise A. Smith, Michael G. Gibbs, and James G. Manning., p.514, August 2010</ref>

In a 1980 survey of 1800 members of amateur astronomer associations by [[Gert Helb]] and [[Hynek]] for CUFOS, 24% responded "yes" to the question "Have you ever observed an object which resisted your most exhaustive efforts at identification?"<ref>{{cite journal |last1=Herb |first1=Gert |last2=Hynek |first2=J. Allen |author-link2=J. Allen Hynek |date=May 2006 |title=The Amateur Astronomer and the UFO Phenomena |version=Reprint |journal=International UFO Reporter |volume=30 |issue=3 |pages=14–16 |location=Chicago |publisher=J. Allen Hynek Center for UFO Studies}}</ref>

====Famous hoaxes====
{{See also|List of UFO-related hoaxes}}
* The [[Maury Island incident]]
* [[George Adamski]], over the space of two decades, made various claims about his meetings with telepathic aliens from nearby planets. He claimed photographs of the [[far side of the Moon]] taken by the Soviet lunar probe [[Luna 3]] in 1959 were fake, and that there were cities, trees and snow-capped mountains on the far side of the Moon. Among copycats was a shadowy British figure named [[Cedric Allingham]].
* Ed Walters, a building contractor, in 1987 allegedly perpetrated a hoax in [[Gulf Breeze, Florida]]. Walters claimed at first having seen a small UFO flying near his home and took some photographs of the craft. Walters reported and documented a series of UFO sightings over a period of three weeks and took several photographs. These sightings became famous, and are collectively referred to as the [[Gulf Breeze UFO incident]]. Three years later, in 1990, after the Walters family had moved, the new residents discovered a model of a UFO poorly hidden in the attic that bore an undeniable resemblance to the craft in Walters' photographs. Most investigators, like the forensic photo expert William G. Hyzer,<ref>{{cite journal |last=Posner |first=Gary P. |date=July 1992 |title=The Gulf Breeze 'UFOs' |journal=Tampa Bay Sounding |publisher=Tampa Bay Mensa |location=Seminole, FL |access-date=July 13, 2013 |url=http://www.gpposner.com/Gulf_Breeze.html |archive-date=July 3, 2013 |archive-url=https://web.archive.org/web/20130703032208/http://www.gpposner.com/Gulf_Breeze.html |url-status=live }}</ref> now consider the sightings to be a hoax.

==Terminology==

===Etymology of key terms===
According to [[Merriam-Webster]], "the term UAP first appeared in the late 1960s, while UFO has been around since 1947".<ref>{{cite web |url=https://www.merriam-webster.com/words-at-play/words-were-watching-uap |title=Words We're Watching: What does 'UAP' mean? |website=Merriam-Webster |access-date=26 June 2023 |archive-url=https://web.archive.org/web/20230417203105/https://www.merriam-webster.com/words-at-play/words-were-watching-uap |archive-date=17 April 2023}}</ref> The [[Oxford English Dictionary]] defines a UFO as "An unidentified flying object; a 'flying saucer'". The first published book to use the word was authored by [[Donald Keyhoe|Donald E. Keyhoe]].<ref name="Keyhoe1953">[[#Keyhoe 1953|Keyhoe 1953]]</ref> The term "UFO" (or "UFOB") was adopted as a standard in 1953 by the [[United States Air Force]] (USAF) to serve as a catch-all for all such reports. In its initial definition, the USAF stated that a "UFOB" was "any airborne object which by performance, aerodynamic characteristics, or unusual features, does not conform to any presently known aircraft or missile type, or which cannot be positively identified as a familiar object". Accordingly, the term was initially restricted to that fraction of cases which remained unidentified after investigation, as the USAF was interested in potential [[national security]] reasons and "technical aspects" (see [[s:Air Force Regulation 200-2, Unidentified Flying Objects Reporting|Air Force Regulation 200-2]]).

During the late 1940s and through the 1950s, UFOs were often referred to popularly as "[[flying saucer]]s" or "flying discs" due to the term being introduced in the context of the Kenneth Arnold incident. The [[Avro Canada]] [[Avro Canada VZ-9 Avrocar|VZ-9AV Avrocar]] was a concept vehicle produced during the 1950s, which was a functional aircraft with a saucer shape.<ref>{{cite web|date=October 9, 2015|title=HOME > VISIT > MUSEUM EXHIBITS > FACT SHEETS > DISPLAY Avro Canada VZ-9AV Avrocar|url=https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195801/avro-canada-vz-9av-avrocar/|work=www.nationalmuseum.af.mil [[United States Air Force]]|access-date=June 22, 2021|archive-date=May 18, 2021|archive-url=https://web.archive.org/web/20210518072042/https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/article/195801/avro-canada-vz-9av-avrocar/|url-status=live}}</ref> UFOs were commonly referred to colloquially, as a "Bogey" by Western military personnel and pilots during the cold war. The term "bogey" was originally used to report anomalies in radar blips, to indicate possible hostile forces that might be roaming in the area.<ref>{{cite web|title=what is a bogey|url=https://searchsecurity.techtarget.com/definition/bogie|access-date=March 24, 2019|website=search security|archive-date=March 24, 2019|archive-url=https://web.archive.org/web/20190324151454/https://searchsecurity.techtarget.com/definition/bogie|url-status=live}}</ref>

The term UFO became more widespread during the 1950s, at first in technical literature, but later in popular use. UFOs garnered considerable interest during the [[Cold War]], an era associated with heightened concerns about national security, and, more recently, in the 2010s, for unexplained reasons.<ref name="NYT-20170424">{{cite news |last=Blumenthal |first=Ralph |title=People Are Seeing U.F.O.s Everywhere, and This Book Proves It |url=https://www.nytimes.com/2017/04/24/science/ufo-sightings-book.html |date=April 24, 2017 |work=[[New York Times]] |access-date=April 24, 2017 |archive-date=November 25, 2020 |archive-url=https://web.archive.org/web/20201125031952/https://www.nytimes.com/2017/04/24/science/ufo-sightings-book.html |url-status=live }}</ref><ref name="AMZ-20170324">{{cite book |last1=Costa |first1=Cheryl |last2=Costa |first2=Linda Miller |title=UFO Sightings Desk Reference: United States of America 2001-2015 |date=March 24, 2017 |publisher=Dragon Lady Media, LLC |isbn=978-1544219233 }}</ref> Nevertheless, various studies have concluded that the phenomenon does not represent a threat, and nor does it contain anything worthy of scientific pursuit (e.g., 1951 [[Flying Saucer Working Party]], 1953 [[Central Intelligence Agency|CIA]] [[Robertson Panel]], USAF [[Project Blue Book]], [[Condon Committee]]).

As an acronym, "UFO" was coined by Captain [[Edward J. Ruppelt]], who headed Project Blue Book, then the USAF's official investigation of UFOs. He wrote, "Obviously the term 'flying saucer' is misleading when applied to objects of every conceivable shape and performance. For this reason the military prefers the more general, if less colorful, name: unidentified flying objects. UFO (pronounced yoo-foe) for short."<ref>[[#Ruppelt|Ruppelt 1956]], Chapter 1: [http://www.nicap.org/rufo/rufo-01.htm "Project Blue Book and the UFO Story"] {{Webarchive|url=https://web.archive.org/web/20130927014715/http://www.nicap.org/rufo/rufo-01.htm |date=September 27, 2013 }}</ref> Other phrases that were used officially and that predate the UFO acronym include "flying flapjack", "flying disc", "unexplained flying discs", and "unidentifiable object".<ref>{{cite web |url=http://vault.fbi.gov/UFO/UFO%20Part%201%20of%2016/view |title=UFO Part 1 of 16 |work=The Vault |publisher=[[Federal Bureau of Investigation]] |location=Washington, D.C. |pages=1–20 |access-date=May 16, 2013 |archive-date=May 12, 2013 |archive-url=https://web.archive.org/web/20130512173143/http://vault.fbi.gov/UFO/UFO%20Part%201%20of%2016/view |url-status=live }}</ref><ref>{{cite web |url=http://www.bluebookarchive.org/page.aspx?PageCode=NARA-PBB1-922 |title=Unidentifiable objects, Williams Field; Chandler, Arizona |last=Aldrich |first=Lynn C. |date=July 14, 1947 |publisher=Project Blue Book Archive |type=Memorandum |id=NARA-PBB1-922 |access-date=May 16, 2013 |archive-url=https://web.archive.org/web/20130928095640/http://www.bluebookarchive.org/page.aspx?PageCode=NARA-PBB1-922 |archive-date=September 28, 2013 |url-status=dead }}</ref><ref name="AP-20130329">{{cite news|last=Contreras|first=Russell|title=FBI 'flying saucers' NM memo bureau's most viewed|url=http://apnews.excite.com/article/20130329/DA5AVRAG0.html|date=March 29, 2013|agency=[[Associated Press]]|access-date=April 1, 2013|archive-date=September 27, 2013|archive-url=https://web.archive.org/web/20130927222146/http://apnews.excite.com/article/20130329/DA5AVRAG0.html|url-status=live}}</ref>

In popular usage, the term UFO came to be used to refer to claims of alien [[spacecraft]],<ref name="Keyhoe1953" /> and because of the public and media ridicule associated with the topic, some [[ufology|ufologists]] and investigators prefer to use terms such as "unidentified aerial phenomenon" (UAP) or simply "anomalous phenomena", as in the name of the National Aviation Reporting Center on Anomalous Phenomena (NARCAP).<ref>{{cite web |url=http://www.narcap.org/newspage.htm |title=On The Radar |last=Roe |first=Ted |website=NARCAP.org |publisher=National Aviation Reporting Center on Anomalous Phenomena (NARCAP) |archive-url=https://web.archive.org/web/20110727111914/http://www.narcap.org/newspage.htm |archive-date=July 27, 2011 |access-date=September 6, 2013 }} See May 17, 2013, NARCAP.org news release: [https://www.facebook.com/permalink.php?id=197024020359733&story_fbid=518978498164282 "'Aliens', 'Alien Spaceships' & Government Coverups"] {{Webarchive|url=https://web.archive.org/web/20210308053137/https://www.facebook.com/permalink.php?id=197024020359733&story_fbid=518978498164282 |date=March 8, 2021 }} on [[Facebook]].</ref> "Anomalous aerial vehicle" (AAV) or "unidentified aerial system" (UAS) are also sometimes used in a military aviation context to describe unidentified targets.<ref name="FighterSweep">{{Cite web |url=https://fightersweep.com/1460/x-files-edition/ |title=2015 FighterSweep.com account of the 2004 Nimitz UFO incident |date=March 14, 2015 |access-date=February 6, 2018 |archive-date=January 20, 2018 |archive-url=https://web.archive.org/web/20180120042042/https://fightersweep.com/1460/x-files-edition/ |url-status=live }}</ref>

More recently, U.S. officials have adopted the term "unidentified aerial phenomenon"<ref name="Hanks2022">{{cite web |author=Micah Hanks |url=https://thedebrief.org/the-pentagon-just-revealed-the-new-name-of-its-uap-investigative-office/ |title=The Pentagon Just Revealed the New Name of Its UAP Investigative Office |publisher=The Debrief |date=July 21, 2022 |access-date=July 24, 2022 |archive-date=July 24, 2022 |archive-url=https://web.archive.org/web/20220724094335/https://thedebrief.org/the-pentagon-just-revealed-the-new-name-of-its-uap-investigative-office/ |url-status=live }}</ref> (UAP), sometimes expanded as "unidentified anomalous phenomenon"<ref name="Furfaro2022">{{cite web |author= Emily Furfaro |url= https://www.nasa.gov/feature/nasa-announces-unidentified-anomalous-phenomena-study-team-members |title= NASA Announces Unidentified Aerial Phenomena Study Team Members |publisher= NASA |date= October 21, 2022 |access-date=December 23, 2022 |archive-date=December 23, 2022 |archive-url= https://web.archive.org/web/20221223015354/https://www.nasa.gov/feature/nasa-announces-unidentified-anomalous-phenomena-study-team-members/ |url-status= live |quote=Editor's Note: This article was updated on December 22, 2022 to reflect an expanded terminology for 'UAP,' going from unidentified aerial phenomena to unidentified anomalous phenomena.}}</ref> (see below). As summarized in ''ETC: A Review of General Semantics'', "aside from UAP's more encompassing description, this term avoids the heavy cultural baggage attached to [[UFO]], whose initial association with [[extraterrestrial life|extraterrestrial]] origins ...sets up a narrow and inflexible framework for honest scientific research."<ref>{{cite journal |last1=Raimer |first1=Mark A. |date=Spring 1999 |title=The War of the Words: Revamping Operational Terminology for UFOs |url=https://www.jstor.org/stable/42579861 |journal=ETC: A Review of General Semantics |volume=56 |issue=1 |pages=53–59 |doi= |jstor=42579861 |access-date=23 June 2023}}</ref> The term UFO now has decades of association with aliens across many areas of culture, popular entertainment, [[UFO conspiracy theories|conspiracy theories]], and [[UFO religion|religious movements]] as considered in ''American Cosmic'' by [[Diana Walsh Pasulka]] (published by [[Oxford University Press|Oxford]] in 2019).<ref>{{cite book |last=Pasulka |first=Diana Walsh |date=2019 |title=American Cosmic: UFOs, Religion, Technology |location=Oxford, UK |publisher=Oxford University Press |isbn=978-0190692889}}</ref> "Unidentified aerial phenomena (UAP), formerly referred to as UFOs, in theory, could include alien spacecraft, but the two aren't synonymous."<ref>{{cite web |url=https://www.defense.gov/News/News-Stories/Article/Article/3368109/dod-working-to-better-understand-resolve-anomalous-phenomena/ |title=US has 'downplayed' the number of UFO sightings: Senator Hawley |first1=Urja |last1=Sinha |first2=Katie |last2=Smith |first3=Joe |last3=Khalil |date=23 June 2023 |work=The Hill |access-date=23 June 2023 |archive-url=https://web.archive.org/web/20230623171937/https://thehill.com/homenews/4062715-us-has-downplayed-the-number-of-ufo-sightings-senator-hawley/https:/thehill.com/homenews/4062715-us-has-downplayed-the-number-of-ufo-sightings-senator-hawley/ |archive-date=23 June 2023}}</ref>

The [[National Defense Authorization Act for Fiscal Year 2023]] (signed into law on December 23, 2022)<ref name="NASA-UAPIST-name-change">{{cite web |url=https://science.nasa.gov/science-red/s3fs-public/atoms/files/UAPIST%20Terms%20of%20Reference%20-%20May%202023-new.pdf |title=Unidentified Anomalous Phenomena Independent Study Team: Terms of Reference |date=18 May 2023 |website=NASA |access-date=26 June 2023 |archive-url=https://web.archive.org/web/20230531192740/https://science.nasa.gov/science-red/s3fs-public/atoms/files/UAPIST%20Terms%20of%20Reference%20-%20May%202023-new.pdf |archive-date=31 May 2023}}</ref> defined "unidentified anomalous phenomena" in {{UnitedStatesCode|50|3373}}(<span class="ltr">n</span>)(<span class="ltr">8</span>) to include not only "airborne objects" but also "submerged objects or devices" and "transmedium objects or devices" that are not immediately identifiable. In 2023, NASA's UAPIST study team changed the official meaning of the "A" in its name from "Aerial" to "Anomalous" to reflect their new mission as an "All-Anomaly" task force.<ref name="NASA-UAPIST-name-change"/><ref name="Furfaro2022"/>

===Extraterrestrial hypothesis===
{{Main|Extraterrestrial hypothesis}}
While technically a ''UFO'' refers to any unidentified flying object, in modern popular culture the term UFO has generally become synonymous with [[alien spacecraft]];<ref>[[#Haines 1979|Haines 1979]], Chapter: "The Zeitgeist of the UFO Phenomenon" by Armando Simón</ref> however, the term ETV (''extra-terrestrial vehicle'') is sometimes used to separate this explanation of UFOs from totally earthbound explanations,<ref>{{Citation
  | last1 = Giere
  | first1 = Ronald N.
  | last2 = Bickle
  | first2 = John
  | last3 = Mauldin
  | first3 = Robert F.
  | title = Understanding Scientific Reasoning
  | publisher = [[Cengage Learning|Wadsworth Publishing]]
  | date = 2006
  | edition = 5th
  | page = 99
  | isbn = 0-15-506326-X
  | oclc = 61369793
  | lccn = 2005922853}}</ref> including the [[cryptoterrestrial hypothesis]], or from other interpretations of the phenomenon such as the [[interdimensional UFO hypothesis|interdimensional hypothesis]], the [[Time-traveler UFO hypothesis|time-traveler hypothesis]] or the [[psychosocial UFO hypothesis|psychosocial hypothesis]].

==Investigations of reports==

UFOs have been subject to investigations over the years that varied widely in scope and scientific rigor. Governments or independent academics in the United States, Canada, the United Kingdom, Japan, Peru, France, Belgium, Sweden, Brazil, Chile, Uruguay, Mexico, Spain, and the [[Soviet Union]] are known to have investigated UFO reports at various times. No official government investigation has ever publicly concluded that UFOs are indisputably real, physical objects, extraterrestrial in origin, or of concern to national defense.

Among the best known government studies are the ghost rockets investigation by the Swedish military (1946–1947), Project Blue Book, previously [[Project Sign]] and [[Project Grudge]], conducted by the USAF from 1947 until 1969, the secret U.S. Army/Air Force [[Green fireballs#Project Twinkle|Project Twinkle]] investigation into [[green fireballs]] (1948–1951), the secret USAF Project Blue Book Special Report No. 14<ref>{{cite web|url=https://archive.org/details/ProjectBlueBookSpecialReport14 |title=Project Blue Book Special Report #14 |website=[[Internet Archive]] |publisher=[[United States Air Force]] |access-date=September 7, 2013}}</ref> by the [[Battelle Memorial Institute]], and the [[Brazilian Air Force]]'s 1977 ''[[Operação Prato]]'' (Operation Saucer). France has had an ongoing investigation (GEPAN/SEPRA/[[GEIPAN]]) within its space agency [[CNES|Centre national d'études spatiales]] (CNES) since 1977; the [[Politics of Uruguay|government of Uruguay]] has had a similar investigation since 1989.

===Prosaic explanations===

{{Main|Identification studies of UFOs}}
[[File:Fata Morgana Example.jpg|A [[Fata Morgana (mirage)|Fata Morgana]], a type of mirage in which objects located ''below'' the astronomical [[horizon]] appear to be hovering in the sky just above the horizon, may be responsible for some UFO sightings.<ref name="Official UFO Investigations in France: the GEPAN/SEPRA Project">[[#Sturrock, et al. 1998|Sturrock, et al. 1998]], Appendix 4: "Electromagnetic-Wave Ducting" by V. R. Eshleman</ref>|thumb]]

Studies show that after careful investigation, the majority of UFOs can be identified as ordinary objects or phenomena. The most commonly found identified sources of UFO reports are:
* astronomical objects ([[List of brightest stars|bright stars]], [[bolide]]s, [[Classical planet|bright planets]], and the [[Moon]])
* aircraft (including [[Military aircraft|military]], [[Civil aviation|civilian]], and [[Experimental aircraft|experimental]] aircraft as well as such peculiarities as [[aerial advertising]], [[missile]] and other [[rocket launch]]es, [[Satellite|artificial satellites]], re-entering [[spacecraft]] including [[space debris]], [[kite]]s, and various [[unmanned aerial vehicle]]s often popularly termed "drones")
* balloons ([[Project Mogul|surveillance balloons]], [[balloon#Decoration or entertainment|toy balloons]], [[weather balloon]]s, large [[research balloon]]s)
* other atmospheric objects and phenomena (birds, [[Lenticular cloud|unusual clouds]], [[flare]]s, [[Plasma (physics)#Complex plasma phenomena|plasma]])
* light phenomena ([[mirage]]s, [[Fata Morgana (mirage)|Fata Morgana]], [[ball lightning]], [[moon dog]]s, [[satellite flare]]s, [[searchlight]]s and other ground lights, etc.)
* psychological effects ([[pareidolia]], [[suggestibility]] and [[False memory|false memories]], [[Mass psychogenic illness|mass psychogenic disorders]], [[optical illusion]]s, and [[hallucination]]s)
* hoaxes

A 1952–1955 [[Project Blue Book Special Report No. 14|study]] by the Battelle Memorial Institute for the USAF included these categories. An individual 1979 study by CUFOS researcher [[Allan Hendry]] found, as did other investigations, that fewer than one percent of cases he investigated were hoaxes and most sightings were actually honest misidentifications of prosaic phenomena. Hendry attributed most of these to inexperience or misperception.<ref>[[#Hendry|Hendry 1979]]</ref>

===Americas===

==== Brazil (1952–2016) ====

[[File:Registro de avistamento de Objeto Voador Não Identificado - OVNI ocorrido em dezembro de 1977, na Bahia.jpg|thumb|A document about a sighting of a UFO that occurred on December 16, 1977, in the state of [[Bahia]], [[Brazil]]]]

On October 31, 2008, the [[Brazilian National Archives|National Archives of Brazil]] began receiving from the Aeronautical Documentation and History Center part of the documentation of the [[Brazilian Air Force]] regarding the investigation of the appearance of UFOs in [[Brazil]]. Currently, this collection gathers cases between 1952 and 2016.<ref>{{Cite news|url=https://www.bbc.com/news/world-latin-america-10947856|title=Brazil to record UFO sightings|date=August 12, 2010|work=BBC News|access-date=April 1, 2018|archive-date=May 4, 2018|archive-url=https://web.archive.org/web/20180504151608/http://www.bbc.com/news/world-latin-america-10947856|url-status=live}}</ref>

==== Chile (c. 1968) ====

In 1968, the [[SEFAA]] (previously CEFAA) began receiving case reports of the general public, civil aviators and the [[Chilean Air Force]] regarding the sightings or the appearance of UFOs in [[Chile]], the initial work was an initiative of Sergio Bravo Flores who led the Chilean Committee for the Study of Unidentified Space Phenomena, supported even by the Chilean Scientific Society. Currently, the organization changed its denomination to SEFAA and its a department of the [[Directorate General of Civil Aviation (Chile)|DGAC]](Chile) which in turn depends on the [[Chilean Air Force]].<ref>{{cite web|url=https://sefaa.dgac.gob.cl/historia-del-cefaa/|title=Origen de la SEFAA|work=SEFAA|location=[[Santiago de Chile]]|access-date=July 3, 2022|archive-date=July 4, 2022|archive-url=https://web.archive.org/web/20220704020202/https://sefaa.dgac.gob.cl/historia-del-cefaa/|url-status=live}}(in spanish)</ref>

====Canada (c. 1950)====

In Canada, the [[Department of National Defence (Canada)|Department of National Defence]] has dealt with reports, sightings and investigations of UFOs across Canada. In addition to conducting investigations into [[crop circle]]s in [[Duhamel, Alberta]], it still considers "unsolved" the [[Falcon Lake Incident|Falcon Lake incident]] in Manitoba and the [[Shag Harbour UFO incident]] in Nova Scotia.<ref>{{cite web |url=http://www.collectionscanada.gc.ca/ufo/ |title=Canada's UFOs: The Search for the Unknown |publisher=[[Library and Archives Canada]] |location=Ottawa |type=Virtual museum |access-date=September 8, 2013 |archive-url=https://web.archive.org/web/20160116131034/http://www.collectionscanada.gc.ca/ufo/ |archive-date=January 16, 2016 |url-status=dead }}</ref>

Early Canadian studies included [[Project Magnet (UFO)|Project Magnet]] (1950–1954) and [[Project Second Storey]] (1952–1954), supported by the [[Defence Research and Development Canada|Defence Research Board]].

====United States====
====Synopsis====
U.S. investigations into UFOs include:
* [[Project Sign]], by the [[Air Materiel Command]] (AMC) USAF, precursor to Project Grudge, 1948.
* [[Ghost rockets]] investigations by the Finnish, Swedish and British militaries, later the US and Greece, 1946–1947.
* [[Project Grudge]], USAF from February 1949, succeeded by Project Blue Book, from March 1952.
* Project Twinkle investigation into [[green fireballs]], by the U.S. Army/Air Force, briefly, from December 1949.
* The [[Central Intelligence Agency Directorate of Science & Technology]] (DS&<span class="ltr">T</span>), study 1952–53.
* [[The Report on Unidentified Flying Objects]], by USAF Cpt (rtd.), later director of Project Blue Book, 1956.
* The [[Identification studies of UFOs#Project Blue Book Special Report No. 14|Project Blue Book Special Report No. 14]] by the Battelle Memorial Institute for USAF, 1951–1954
* The [[Aerial Phenomena Research Organization]] (APRO), a private research group, 1952–1988.
* The [[Robertson Panel]] was a scientific committee which met in January 1953 to review the Project Blue Book report January 1953
* The [[Brookings Report]], ''Proposed Studies on the Implications of Peaceful Space Activities for Human Affairs'', in conjunction with NASA's Committee on Long-Range Studies, reported to Congress 1960
* The [[Condon Committee]], an informal University of Colorado UFO Project funded by the USAF, 1966 to 1968.
* The [[RAND Corporation]] study, a private and internal study, 1968.<ref>[[#Kocher|Kocher 1968]]</ref>
* The [[Mutual UFO Network]] (MUFON), is a US-based, civilian, non-profit, volunteer organization studying reported UFO sightings, May 1969 and continuing.
* The [[National Investigations Committee On Aerial Phenomena]] (NICAP) is a UFO research group most active in the United States from the 1950s to the 1980 and remains as an informational depository on UFO phenomena.
* The [[Center for UFO Studies]] (CUFOS), a privately funded UFO research group, 1973 and continuing.
* The [[Peter A. Sturrock|Sturrock panel]], private investigation arising from the [[Society for Scientific Exploration]], 1982.
* The [[Advanced Aerospace Threat Identification Program]] which was funded from 2007 to 2012.<ref name="NYT-20171216"/><ref name="NYT-20200514"/>
* The [[All-domain Anomaly Resolution Office]], a continuing program within the United States [[Office of Naval Intelligence]] which was acknowledged in 2017.
* The ''Airborne Object Identification and Management Synchronization Group'', the Pentagon, to investigate unidentified objects that may compromise the airspace of the United States, from November 24, 2021, ongoing.<ref name="WP-20211124">{{cite news |last=Demirjian |first=Karoun |title=Pentagon will track unexplained airborne objects through new intelligence group |url=https://www.washingtonpost.com/national-security/2021/11/24/ufos-pentagon/ |date=November 24, 2021 |newspaper=[[The Washington Post]] |access-date=November 24, 2021 |archive-date=November 25, 2021 |archive-url=https://web.archive.org/web/20211125085817/https://www.washingtonpost.com/national-security/2021/11/24/ufos-pentagon/ |url-status=live }}</ref>

In addition to these, thousands of documents released under [[Freedom of Information Act (United States)|FOIA]] also indicate that many U.S. intelligence agencies collected (and still collect) information on UFOs. These agencies include the [[Defense Intelligence Agency]] (DIA), [[FBI]],<ref name="AP-20130329" /> CIA, [[National Security Agency]] (NSA), as well as military intelligence agencies of the Army and [[United States Navy|U.S. Navy]], in addition to the Air Force.<ref group="note">Many of these documents are now online at the FOIA websites of these agencies such as the {{cite web |url=http://foia.fbi.gov/foiaindex/ufo.htm |title=FBI FOIA site |archive-url=https://web.archive.org/web/20080524114748/http://foia.fbi.gov/foiaindex/ufo.htm |archive-date=May 24, 2008 }}, as well as private websites such as [http://www.theblackvault.com/ The Black Vault] {{Webarchive|url=https://web.archive.org/web/20110902090822/http://www.theblackvault.com/ |date=September 2, 2011 }}, which has an archive of several thousand U.S. government UFO-related documents from the USAF, Army, CIA, DIA, DOD, and NSA.</ref>

=====USAAF and FBI response to the 1947 sightings=====
{{Unbalanced section|date=November 2021}}
Following the large U.S. surge in sightings in June and early July 1947, on July 9, 1947, [[United States Army Air Forces]] (USAAF) intelligence, in cooperation with the FBI,<ref name="AP-20130329" /> began a formal investigation into selected sightings with characteristics that could not be immediately rationalized, such as Kenneth Arnold's. The USAAF used "all of its top scientists" to determine whether "such a phenomenon could, in fact, occur". The research was "being conducted with the thought that the flying objects might be a celestial phenomenon," or that "they might be a foreign body mechanically devised and controlled."<ref>{{cite web |title=Federal Bureau of Investigation FOIA Documents - Unidentified Flying Objects |url=http://www.gutenberg.org/files/25706/25706.txt |url-status=live |archive-url=https://web.archive.org/web/20121110121822/http://www.gutenberg.org/files/25706/25706.txt |archive-date=November 10, 2012 |access-date=September 7, 2013 |website=[[Project Gutenberg]]}} Internal FBI memo from E. G. Fitch to [[D. M. Ladd]] concerning a request by General George F. Schulgen, Chief of the Requirements Intelligence Branch of Army Air Corps Intelligence, for the FBI to help with their investigation of UFO reports.</ref> Three weeks later in a preliminary defense estimate, the air force investigation decided that, "This 'flying saucer' situation is not all imaginary or seeing too much in some natural phenomenon. Something is really flying around."<ref>[[#Hall & Connors|Hall & Connors 1998]], p. 83</ref>

A further review by the intelligence and technical divisions of the [[Air Force Logistics Command|Air Materiel Command]] at [[Wright-Patterson Air Force Base|Wright Field]] reached the same conclusion. It reported that "the phenomenon is something real and not visionary or fictitious," and there were disc-shaped objects, metallic in appearance, as big as man-made aircraft. They were characterized by "extreme rates of climb [and] maneuverability", general lack of noise, absence of a trail, occasional formation flying, and "evasive" behavior "when sighted or contacted by friendly aircraft and radar", suggesting a controlled craft. It was therefore recommended in late September 1947 that an official Air Force investigation be set up. It was also recommended that other government agencies should assist in the investigation.<ref group="note">The so-called [http://www.majesticdocuments.com/pdf/twiningopinionamc_23sept47.pdf Twining memo of September 23, 1947] {{Webarchive|url=https://web.archive.org/web/20090226081323/http://www.majesticdocuments.com/pdf/twiningopinionamc_23sept47.pdf |date=February 26, 2009 }}, by future USAF Chief of Staff, General [[Nathan Farragut Twining|Nathan Twining]], specifically recommended intelligence cooperation with the Army, Navy, [[United States Atomic Energy Commission|Atomic Energy Commission]], the Defense Department's Joint Research and Development Board, Air Force Scientific Advisory Board, [[National Advisory Committee for Aeronautics]] (NACA), Project [[RAND]], and the [[Nuclear aircraft|Nuclear Energy for the Propulsion of Aircraft]] (NEPA) project.</ref>

=====USAF=====

====== Projects Sign (1947–1949), Grudge (1948–1951), and Blue Book (1951–1970) ======
{{main|Project Sign|Project Grudge|Project Blue Book}}
Project Sign's final report, published in early 1949, stated that while some UFOs appeared to represent actual aircraft, there was not enough data to determine their origin.<ref name="Blum1990">Blum, Howard, Out There: The Government's Secret Quest for Extraterrestrials. Simon and Schuster, 1990</ref>

The Air Force's Project Sign was created at the end of 1947, and was one of the earliest government studies to come to a secret extraterrestrial conclusion. In August 1948, Sign investigators wrote a top-secret intelligence estimate to that effect, but the [[Chief of Staff of the United States Air Force|Air Force Chief of Staff]] [[Hoyt Vandenberg]] ordered it destroyed. The existence of this suppressed report was revealed by several insiders who had read it, such as astronomer and USAF consultant J. Allen Hynek and Capt. Edward J. Ruppelt, the first head of the USAF's Project Blue Book.<ref>[[#Ruppelt|Ruppelt 1956]], Chapter 3: [http://www.nicap.org/rufo/rufo-03.htm "The Classics"] {{Webarchive|url=https://web.archive.org/web/20070906190034/http://www.nicap.org/rufo/rufo-03.htm |date=September 6, 2007 }}</ref>

Another highly classified U.S. study was conducted by the CIA's Office of Scientific Investigation (OS/I) in the latter half of 1952 in response to orders from the [[United States National Security Council|National Security Council]] (NSC). This study concluded UFOs were real physical objects of potential threat to national security. One OS/I memo to the CIA Director (DCI) in December read that "the reports of incidents convince us that there is something going on that must have immediate attention&nbsp;... Sightings of unexplained objects at great altitudes and traveling at high speeds in the vicinity of major U.S. defense installations are of such a nature that they are not attributable to natural phenomena or any known types of aerial vehicles."<ref name="auto">{{cite web |url=https://www.cia.gov/library/center-for-the-study-of-intelligence/csi-publications/csi-studies/studies/97unclass/ufo.html |title=CIA's Role in the Study of UFOs, 1947–90 |last=Haines |first=Gerald K. |date=1997 |publisher=[[Central Intelligence Agency]] |oclc=713270503 |access-date=July 13, 2013 |archive-date=October 1, 2019 |archive-url=https://web.archive.org/web/20191001174318/https://www.cia.gov/library/center-for-the-study-of-intelligence/csi-publications/csi-studies/studies/97unclass/ufo.html |url-status=dead }}</ref>

The matter was considered so urgent that OS/I drafted a memorandum from the DCI to the NSC proposing that the NSC establish an investigation of UFOs as a priority project throughout the intelligence and the defense research and development community. It also urged the DCI to establish an external research project of top-level scientists, now known as the Robertson Panel to analyze the problem of UFOs. The OS/I investigation was called off after the Robertson Panel's negative conclusions in January 1953.<ref name="auto"/>

Project Sign was dismantled and became Project Grudge at the end of 1948. Angered by the low quality of investigations by Grudge, the Air Force Director of Intelligence reorganized it as Project Blue Book in late 1951, placing Ruppelt in charge. [[J. Allen Hynek]], a trained astronomer who served as a scientific advisor for Project Blue Book, was initially skeptical of UFO reports, but eventually came to the conclusion that many of them could not be satisfactorily explained and was highly critical of what he described as "the cavalier disregard by Project Blue Book of the principles of scientific investigation".<ref>[[#Hynek 1972|Hynek 1972]], p. 76</ref> Leaving government work, he founded the privately funded [[Center for UFO Studies|CUFOS]], to whose work he devoted the rest of his life. Other private groups studying the phenomenon include the [[Mutual UFO Network|MUFON]], a grassroots organization whose investigator's handbooks go into great detail on the documentation of alleged UFO sightings.

====== USAF Regulation 200-2 (1953–1954) ======

[[s:Air Force Regulation 200-2, Unidentified Flying Objects Reporting|Air Force Regulation 200-2]],<ref name="AFD-070703-004">{{cite web |url=http://www.foia.af.mil/shared/media/document/AFD-070703-004.pdf |title=AFD-070703-004.pdf |work=Air Force Freedom of Information Act |publisher=United States Air Force |access-date=September 7, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20120910051437/http://www.foia.af.mil/shared/media/document/AFD-070703-004.pdf |archive-date=September 10, 2012  }}</ref> issued in 1953 and 1954, defined an Unidentified Flying Object ("UFOB") as "any airborne object which by performance, aerodynamic characteristics, or unusual features, does not conform to any presently known aircraft or missile type, or which cannot be positively identified as a familiar object." The regulation also said UFOBs were to be investigated as a "possible threat to the security of the United States" and "to determine technical aspects involved." The regulation went on to say that "it is permissible to inform news media representatives on UFOB's when the object is positively identified as a familiar object" but added: "For those objects which are not explainable, only the fact that ATIC [Air Technical Intelligence Center] will analyze the data is worthy of release, due to many unknowns involved."<ref name="AFD-070703-004" />

===== Blue Book and the Condon Committee (1968–1970) =====
{{main|Condon Committee}}

A public research effort conducted by the Condon Committee for the USAF and published as the Condon Report arrived at a negative conclusion in 1968.<ref name="COMETA" /> Blue Book closed down in 1970, using the Condon Committee's negative conclusion as a rationale, thus ending official Air Force UFO investigations. However, a 1969 USAF document, known as the Bolender memo, along with later government documents, revealed that non-public [[Federal government of the United States|U.S. government]] UFO investigations continued after 1970. The Bolender memo first stated that "reports of unidentified flying objects that could affect national security&nbsp;... are not part of the Blue Book system," indicating that more serious UFO incidents already were handled outside the public Blue Book investigation. The memo then added, "reports of UFOs which could affect national security would continue to be handled through the standard Air Force procedures designed for this purpose."<ref group="note">For example, current USAF general reporting procedures are in [http://www.theblackvault.com/documents/ufos/AFI10-206.pdf Air Force Instruction (AFI)10-206] {{Webarchive|url=https://web.archive.org/web/20080618065117/http://www.theblackvault.com/documents/ufos/AFI10-206.pdf |date=June 18, 2008 }}. Section 5.7.3 (p. 64) lists sightings of "unidentified flying objects" and "aircraft of unconventional design" as separate categories from potentially hostile but conventional, unidentified aircraft, missiles, surface vessels, or submarines. Additionally, "unidentified objects" detected by missile warning systems, creating a potential risk of nuclear war, are covered by Rule 5E (p.35).</ref>

In the late 1960s, a chapter on UFOs in the Space Sciences course at the [[United States Air Force Academy|U.S. Air Force Academy]] gave serious consideration to possible extraterrestrial origins. When word of the curriculum became public, in 1970, the Air Force issued a statement to the effect that the book was outdated and cadets instead were being informed of the [[Condon Committee|Condon Report]]'s negative conclusion.<ref>{{cite web |url=http://www.cufon.org/cufon/afu.htm |title=Introductory Space Science |website=CUFON.org |publisher=Computer UFO Network (CUFON) |location=West Jacksonville, FL |access-date=May 16, 2013 |archive-date=May 30, 2013 |archive-url=https://web.archive.org/web/20130530172640/http://www.cufon.org/cufon/afu.htm |url-status=live }} Air Force Academy UFO material.</ref>

Controversy surrounded the report, both before and after its release. It has been observed that the report was "harshly criticized by numerous scientists, particularly at the powerful AIAA&nbsp;... [which] recommended moderate, but continuous scientific work on UFOs."<ref name="COMETA" /> In an address to the [[American Academy of Arts and Sciences|AAAS]], [[James E. McDonald]] said he believed science had failed to mount adequate studies of the problem and criticized the Condon Report and earlier studies by the USAF as scientifically deficient. He also questioned the basis for Condon's conclusions<ref name="default">{{cite conference |first=James E. |last=McDonald |title=Science in Default: Twenty-Two Years of Inadequate UFO Investigations |conference=[[American Association for the Advancement of Science]], 134th Meeting |book-title=UFO's: A Scientific Debate |editor1-last=Sagan |editor1-first=Carl |editor1-link=Carl Sagan |editor2-last=Page |editor2-first=Thornton |url=https://archive.org/details/ufosascientificd0000unse_n5n6 |edition=Reprint |orig-year=Originally published 1972 |date=1974 |publisher=[[W. W. Norton & Company]] |location=New York |isbn=978-0-393-00739-8 |oclc=934695 |lccn=72004572 |access-date=March 30, 2011  |url-access=registration }}</ref> and argued that the reports of UFOs have been "laughed out of scientific court".<ref name="McDonald" /> J. Allen Hynek, an astronomer who worked as a USAF consultant from 1948, sharply criticized the Condon Committee Report and later wrote two nontechnical books that set forth the case for continuing to investigate UFO reports.

Ruppelt recounted his experiences with Project Blue Book, a USAF investigation that preceded Condon's.<ref>[[#Ruppelt|Ruppelt 1956]]</ref>

====FOIA release of documents in 1978====
According to a 1979 [[New York Times]] report, "records from the C.I.A., the F.B.I. and other Federal agencies" ("about 900 documents — nearly 900 pages of memos, reports and correspondence") obtained in 1978 through the Freedom of Information Act request, indicate that『despite official pronouncements for decades that U.F.O.'s were nothing more than misidentified aerial objects and as such were no cause for alarm ... the phenomenon has aroused much serious behind‐the‐scenes concern』in the US government. In particular, officials were concerned over the "approximately 10%" of UFO sightings which remained unexplained, and whether they might be Soviet aircraft and a threat to national security.<ref name="Huyghe-1979-NYT">{{cite news |last1=Huyghe |first1=Patrick |title=U.F.O. FILES: THE UNTOLD STORY |work=The New York Times |url=https://www.nytimes.com/1979/10/14/archives/ufo-files-the-untold-story.html |access-date=November 9, 2021 |agency=New York Times |date=October 14, 1979 |archive-date=November 9, 2021 |archive-url=https://web.archive.org/web/20211109023957/https://www.nytimes.com/1979/10/14/archives/ufo-files-the-untold-story.html |url-status=live }}</ref>  Officials were concerned about the "risk of false alerts", of "falsely identifying the real as phantom", and of mass hysteria caused by sightings. In 1947, Brigadier General George F. Schulgen of Army Air Corps Intelligence, warned "the first reported sightings might have been by individuals of Communist sympathies with the view to causing hysteria and fear of a secret Russian weapon."<ref name="Huyghe-1979-NYT"/>

===== White House statement of November 2011 =====
In November 2011, the [[White House]] released an official response to two petitions asking the U.S. government to acknowledge formally that aliens have visited this planet and to disclose any intentional withholding of government interactions with extraterrestrial beings. According to the response:
{{blockquote|The U.S. government has no evidence that any life exists outside our planet, or that an extraterrestrial presence has contacted or engaged any member of the human race...no credible information to suggest that any evidence is being hidden from the public's eye....|Statement by the White House<ref name="WhiteHouse">{{cite web|last=Larson|first=Phil|title=Searching for ET, But No Evidence Yet|url=https://wwws.whitehouse.gov/petitions#!/response/searching-et-no-evidence-yet|date=November 5, 2011|publisher=[[White House]]|access-date=2013-09-06|url-status=dead|archive-url=https://web.archive.org/web/20111124052154/https://wwws.whitehouse.gov/Petitions#!/response/searching-et-no-evidence-yet|archive-date=November 24, 2011|df=mdy-all}}</ref><ref name="Atkinson">{{cite news |first=Nancy |last=Atkinson |url=http://www.universetoday.com/90717/no-alien-visits-or-ufo-coverups-white-house-says/ |title=No Alien Visits or UFO Coverups, White House Says |date=November 5, 2011 |work=[[Universe Today]] |location=Courtenay, B.C. |access-date=November 6, 2011 |archive-date=January 18, 2019 |archive-url=https://web.archive.org/web/20190118163408/https://www.universetoday.com/90717/no-alien-visits-or-ufo-coverups-white-house-says/ |url-status=live }}</ref>}}

The response further noted that efforts, like [[Search for extraterrestrial intelligence|SETI]] and NASA's ''[[Kepler (spacecraft)|Kepler]]'' space telescope and [[Mars Science Laboratory]], continue looking for [[life|signs of life]]. The response noted "odds are pretty high" that there may be life on other planets but "the odds of us making contact with any of them—especially any [[extraterrestrial intelligence|intelligent ones]]—are extremely small, given the distances involved."<ref name="WhiteHouse"/><ref name="Atkinson"/>

=====ODNI report 2021=====
On June 25, 2021, the [[Office of the Director of National Intelligence]] released a report on UAPs.<ref>{{cite news |last1=Gabbatt |first1=Adam |title=It came out of the sky: US releases highly anticipated UFO report |url=https://www.theguardian.com/us-news/2021/jun/25/ufos-us-government-report |work=The Guardian |date=June 25, 2021 |language=en |access-date=June 26, 2021 |archive-date=June 26, 2021 |archive-url=https://web.archive.org/web/20210626025006/https://www.theguardian.com/us-news/2021/jun/25/ufos-us-government-report |url-status=live }}</ref> The report found that the UAPTF was unable to identify 143 objects spotted between 2004 and 2021. The report said that 18 of these featured unusual movement patterns or flight characteristics, adding that more analysis was needed to determine if those sightings represented "breakthrough" technology. The report said that "some of these steps are resource-intensive and would require additional investment."<ref name="dni_Preliminary_Assessment">{{cite web |title=Preliminary Assessment: Unidentified Aerial Phenomena |publisher=[[Office of the Director of National Intelligence]] |date=June 25, 2021 |access-date=June 25, 2021 |url=https://www.dni.gov/files/ODNI/documents/assessments/Prelimary-Assessment-UAP-20210625.pdf |archive-date=July 26, 2021 |archive-url=https://web.archive.org/web/20210726114054/https://www.dni.gov/files/ODNI/documents/assessments/Prelimary-Assessment-UAP-20210625.pdf |url-status=live }}</ref> The report did not link the sightings to extraterrestrial life.<ref name="APmerchant">{{cite news |last1=Merchant |first1=Nomaan |title=No ET, no answers: Intel report is inconclusive about UFOs |url=https://apnews.com/article/technology-government-and-politics-f5f24502d97072fd4bef34b6fe36c81d |website=apnews.com |date=June 25, 2021 |agency=Associated Press |access-date=June 25, 2021 |archive-date=June 25, 2021 |archive-url=https://web.archive.org/web/20210625210913/https://apnews.com/article/technology-government-and-politics-f5f24502d97072fd4bef34b6fe36c81d |url-status=live }}</ref><ref>{{cite news |last1=Kube |first1=Courtney |last2=Edelman |first2=Adam |title=UFO report: Government can't explain 143 of 144 mysterious flying objects, blames limited data |url=https://www.nbcnews.com/politics/politics-news/ufo-report-government-can-t-explain-143-144-mysterious-flying-n1272390 |work=NBC News |date=June 25, 2021 |language=en |access-date=June 26, 2021 |archive-date=June 26, 2021 |archive-url=https://web.archive.org/web/20210626023614/https://www.nbcnews.com/politics/politics-news/ufo-report-government-can-t-explain-143-144-mysterious-flying-n1272390 |url-status=live }}</ref>

====Uruguay (c. 1989)====

The [[Uruguayan Air Force]] has conducted UFO investigations since 1989 and reportedly analyzed 2,100 cases of which they regard approximately 2% as lacking explanation.<ref>{{cite news |title=Hay aún 40 casos de ovnis sin explicación |first=Daniel |last=Isgleas |url=http://historico.elpais.com.uy/090607/pnacio-421863/nacional/Hay-aun-40-casos-de-ovnis-sin-explicacion/ |work=[[El País (Uruguay)|El País]] |publisher=[[Teledoce]] |location=Montevideo |date=June 7, 2009 |access-date=September 10, 2013 |language=es |archive-date=November 16, 2013 |archive-url=https://web.archive.org/web/20131116102645/http://historico.elpais.com.uy/090607/pnacio-421863/nacional/Hay-aun-40-casos-de-ovnis-sin-explicacion/ |url-status=live }}</ref>

===Europe===

==== France (1977–2008) ====

In March 2007, the French space agency [[CNES]] published an archive of UFO sightings and other phenomena online.<ref name="geipan">{{cite web |url=http://www.cnes-geipan.fr/ |title=GEIPAN: Le GEIPAN |work=[[GEIPAN|Groupe d'Études et d'Informations sur les Phénomènes Aérospatiaux Non Identifiés]] (GEIPAN) |publisher=[[Centre national d'études spatiales]] (CNES) |location=Paris |access-date=May 16, 2013 |archive-date=February 19, 2011 |archive-url=https://web.archive.org/web/20110219094957/http://www.cnes-geipan.fr/ |url-status=live }}</ref>

French studies include GEPAN/SEPRA/[[GEIPAN]] within CNES (French space agency), the longest ongoing government-sponsored investigation. About 22% of the 6,000 cases studied remain unexplained.<ref name="GEIPAN statistics summary">{{cite web|url=http://www.cnes.fr/web/CNES-en/5039-a-history-of-uap-research-at-cnes.php|title=A history of UAP research at CNES|publisher=[[CNES]]|access-date=October 6, 2014|archive-date=October 6, 2014|archive-url=https://web.archive.org/web/20141006155415/http://www.cnes.fr/web/CNES-en/5039-a-history-of-uap-research-at-cnes.php|url-status=live}}</ref> The official opinion of GEPAN/SEPRA/GEIPAN has been neutral, stating on their [[FAQ]] page that their mission is fact-finding for the scientific community, not rendering an opinion. They add they can neither prove nor disprove the Extraterrestrial Hypothesis (ETH), but their Steering Committee's clear position is that they cannot discard the possibility that some fraction of the very strange 22% of unexplained cases might be due to distant and advanced civilizations.<ref>{{cite web|url=https://www.geipan.fr/fr/faq-page?_x_tr_sl=fr&_x_tr_tl=en&_x_tr_hl=en#n58794| title=Autres Liens |access-date=October 6, 2014}}</ref>

Possibly their bias may be indicated by their use of the terms "PAN" (French) or "UAP" (English equivalent) for "Unidentified ''Aerospace'' Phenomenon" (whereas "UAP" is normally used by English organizations stands for "Unidentified ''Aerial'' Phenomenon", a more neutral term). In addition, the three heads of the studies have gone on record in stating that UFOs were real physical flying machines beyond our knowledge or that the best explanation for the most inexplicable cases was an extraterrestrial one.<ref>{{cite web |url=http://www.ufoevidence.org/documents/doc2008.htm |title=Official French Gov't UFO study project to resume with new director |date=October 2005 |publisher=ufoevidence.org |location=Seattle, WA |access-date=July 13, 2013 |archive-date=May 2, 2013 |archive-url=https://web.archive.org/web/20130502192445/http://ufoevidence.org/documents/doc2008.htm |url-status=live }}</ref><ref>{{cite web |url=http://www.ufoevidence.org/documents/doc1627.htm |title='Yes, UFOs exist': Position statement by SEPRA head, Jean-Jacques Velasco |orig-year=Originally published in ''[[La Dépêche du Midi]]'' |date=April 18, 2004 |publisher=ufoevidence.org |location=Seattle, WA |access-date=July 13, 2013 |archive-date=April 8, 2013 |archive-url=https://web.archive.org/web/20130408232437/http://www.ufoevidence.org/documents/doc1627.htm |url-status=live }}</ref><ref>{{cite web |url=http://www.ufoevidence.org/documents/doc1626.htm |title=Assessment of the UFO phenomenon by GEPAN (1978) |publisher=ufoevidence.org |location=Seattle, WA |access-date=July 13, 2013 |archive-date=April 8, 2013 |archive-url=https://web.archive.org/web/20130408232427/http://www.ufoevidence.org/documents/doc1626.htm |url-status=live }}</ref> In 2007, the CNES's own report stated that, at that time, 28% of sightings remained unidentified.<ref>{{Cite web |url=https://cnes.fr/en/web/CNES-en/5866-geipan-uap-investigation-unit-opens-its-files.php |title=CNES report, March 26, 2007 |date=April 23, 2015 |access-date=January 8, 2023 |archive-date=January 8, 2023 |archive-url=https://web.archive.org/web/20230108170520/https://cnes.fr/en/web/CNES-en/5866-geipan-uap-investigation-unit-opens-its-files.php |url-status=live }}</ref>

In 2008, Michel Scheller, president of the [[Association Aéronautique et Astronautique de France]] (3AF), created the Sigma Commission. Its purpose was to investigate UFO phenomena worldwide.<ref>{{cite web |url=http://www.dailymotion.com/video/x98y3k_ovni-nouvelle-commission-denquete-3_tech |title=Ovni-nouvelle-commission-denquete-3AF-PAN (Partie 1) |website=[[Dailymotion]] |date=May 11, 2009 |publisher=[[Orange (telecommunications)|Orange]] |location=Paris |access-date=January 11, 2014 |archive-date=January 6, 2014 |archive-url=https://web.archive.org/web/20140106220709/http://www.dailymotion.com/video/x98y3k_ovni-nouvelle-commission-denquete-3_tech |url-status=live }}</ref> A progress report published in May 2010 stated that the central hypothesis proposed by the [[COMETA report]] is perfectly credible.<ref>{{cite web |url=http://www.openminds.tv/wp-content/uploads/Rapport_Etape_Com.SIGMA_Juin2010.pdf |title=Rapport d'étape de la Commission Sigma/3AF |date=May 31, 2010 |publisher=[[Association Aéronautique et Astronautique de France]] |location=Paris |access-date=January 11, 2014 |archive-date=September 24, 2015 |archive-url=https://web.archive.org/web/20150924061130/http://www.openminds.tv/wp-content/uploads/Rapport_Etape_Com.SIGMA_Juin2010.pdf |url-status=live }}</ref> In December 2012, the final report of the Sigma Commission was submitted to Scheller. Following the submission of the final report, the Sigma2 Commission is to be formed with a mandate to continue the scientific investigation of UFO phenomena.<ref>{{cite web |url=http://www.3af.fr/article/en-direct-de-3af/sigma-2 |title=Sigma 2 |last=Dini |first=Luc |date=January 10, 2013 |website=3AF |publisher=Association Aéronautique et Astronautique de France |location=Paris |access-date=January 11, 2014 |archive-date=February 13, 2014 |archive-url=https://web.archive.org/web/20140213092211/http://www.3af.fr/article/en-direct-de-3af/sigma-2 |url-status=live }}</ref><ref>{{cite interview |last=Boudier |first= Alain |interviewer=Alexandre |title=Alexandre – Alain Boudier – Sygma & 3AF |url=http://rim951.fr/?p=2537 |work=RimLive.com |location=Paris |date=June 20, 2013 |access-date=January 11, 2014}}</ref>

==== Italy (1933–2005) ====

Alleged UFO sightings gradually increased since the war, peaking in 1978 and 2005. The total number of sightings since 1947 are 18,500, of which 90% are identifiable.<ref>{{cite web|url=http://www.ufo.it/ufo1bis.htm?l-l=en|title=And Ufology UFO Italy UFO sightings, not Flying Saucers, Aliens or Extraterrestrials|publisher=Ufo.it|access-date=October 6, 2014|archive-date=October 6, 2014|archive-url=https://web.archive.org/web/20141006163047/http://www.ufo.it/ufo1bis.htm?l-l=en|url-status=live}}</ref>

==== United Kingdom (1951–2009) ====
{{Update section|date=December 2020}}
The UK's [[Flying Saucer Working Party]] published its final report in June 1951, which remained secret for over fifty years. The Working Party concluded that all UFO sightings could be explained as misidentifications of ordinary objects or phenomena, optical illusions, psychological misperceptions/aberrations, or hoaxes. The report stated: "We accordingly recommend very strongly that no further investigation of reported mysterious aerial phenomena be undertaken, unless and until some material evidence becomes available."<ref name="FSWP">{{cite web |url=http://www.theblackvault.com/documents/ufos/UK/DEFE44-119.pdf |title=Unidentified Flying Objects |date=June 1951 |website=The Black Vault |publisher=John Greenewald |id=DSI/JTIC Report No. 7 |location=Northridge, CA |access-date=September 16, 2013 |archive-date=June 1, 2012 |archive-url=https://web.archive.org/web/20120601042337/http://www.theblackvault.com/documents/ufos/UK/DEFE44-119.pdf |url-status=live }}</ref>

Eight file collections on UFO sightings, dating from 1978 to 1987, were first released on May 14, 2008, to [[The National Archives (United Kingdom)|The National Archives]] by the [[Ministry of Defence (United Kingdom)|Ministry of Defence]] (MoD).<ref name="nationalarchivesUFO">{{cite web |url=http://www.nationalarchives.gov.uk/ufos/ |title=UFO files |publisher=[[The National Archives (United Kingdom)|The National Archives]] |location=Kew |access-date=September 10, 2013 |archive-date=February 24, 2011 |archive-url=https://web.archive.org/web/20110224203714/http://www.nationalarchives.gov.uk/ufos/ |url-status=live }}</ref> Although kept secret from the public for many years, most of the files have low levels of classification and none are classified Top Secret. 200 files are set to be made public by 2012. The files are correspondence from the public sent to the British government and officials, such as the MoD and [[Margaret Thatcher]]. The MoD released the files under the [[Freedom of information in the United Kingdom|Freedom of Information Act]] due to requests from researchers.<ref>{{cite news |title=Files released on UFO sightings |url=http://news.bbc.co.uk/2/hi/uk_news/7398108.stm |work=[[BBC News]] |publisher=BBC |location=London |date=May 14, 2008 |access-date=May 16, 2013 |archive-date=July 20, 2008 |archive-url=https://web.archive.org/web/20080720115509/http://news.bbc.co.uk/2/hi/uk_news/7398108.stm |url-status=live }}</ref> These files include, but are not limited to, UFOs over [[Liverpool]] and [[Waterloo Bridge]] in London.<ref>{{cite news |title=The truth is out there: Britons 'spotted' UFOs, records say |url=http://afp.google.com/article/ALeqM5j0OnawpQKsmDXbJAce-OI5EiUgHQ |agency=[[Agence France-Presse|AFP]] |location=London |date=May 13, 2008 |access-date=May 16, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130605221509/http://afp.google.com/article/ALeqM5j0OnawpQKsmDXbJAce-OI5EiUgHQ |archive-date=June 5, 2013  }}</ref>

On October 20, 2008, more UFO files were released. One case released detailed that in 1991 an Alitalia passenger aircraft was approaching [[London Heathrow Airport]] when the pilots saw what they described as a "[[cruise missile]]" fly extremely close to the cockpit. The pilots believed a collision was imminent. UFO expert David Clarke says this is one of the most convincing cases for a UFO he has come across.<ref>{{cite news |title=Airliner had near miss with UFO |url=http://news.bbc.co.uk/1/hi/uk/7679145.stm |work=BBC News |publisher=BBC |location=London |date=October 20, 2008 |access-date=May 16, 2013 |archive-date=October 23, 2008 |archive-url=https://web.archive.org/web/20081023152515/http://news.bbc.co.uk/1/hi/uk/7679145.stm |url-status=live }}</ref>

A secret study of UFOs was undertaken for the Ministry of Defence between 1996 and 2000 and was code-named Project Condign. The resulting report, titled "Unidentified Aerial Phenomena in the UK Defence Region", was publicly released in 2006, but the identity and credentials of whoever constituted Project Condign remains classified. The report confirmed earlier findings that the main causes of UFO sightings are misidentification of man-made and natural objects. The report noted: "No artefacts of unknown or unexplained origin have been reported or handed to the UK authorities, despite thousands of Unidentified Aerial Phenomena reports. There are no [[Signals intelligence|SIGINT]], [[Signals intelligence|ELINT]] or radiation measurements and little useful video or still [[Imagery intelligence|IMINT]]."<ref name="auto1">{{cite web |url=http://www.mod.uk/NR/rdonlyres/BA0DA42F-2C56-431E-98F6-19CD45EE7D43/0/uap_vol3_executive_summary_pg2_paras4_and_7.pdf |archive-url=http://webarchive.nationalarchives.gov.uk/20121026065214/http://www.mod.uk/NR/rdonlyres/BA0DA42F-2C56-431E-98F6-19CD45EE7D43/0/uap_vol3_executive_summary_pg2_paras4_and_7.pdf |url-status=dead |archive-date=October 26, 2012 |title=Unidentified Aerial Phenomena in the UK Air Defence Region |volume=3 |author=Defence Intelligence Staff |author-link=Defence Intelligence |date=December 2000 |publisher=The National Archives |location=Kew |page=2 |id=55/2/00 |access-date=September 10, 2013}} See also The National Archives site: [http://webarchive.nationalarchives.gov.uk/20121026065214/http://www.mod.uk/DefenceInternet/FreedomOfInformation/PublicationScheme/SearchPublicationScheme/UapInTheUkAirDefenceRegionVolume3.htm "Unidentified Aerial Phenomena (UAP) in the UK Air Defence Region"] for archived documents.</ref>

It concluded: "There is no evidence that any UAP, seen in the UKADR [UK Air Defence Region], are incursions by air-objects of any intelligent (extraterrestrial or foreign) origin, or that they represent any hostile intent." A little-discussed conclusion of the report was that novel meteorological plasma phenomenon akin to [[ball lightning]] are responsible for "the majority, if not all" of otherwise inexplicable sightings, especially reports of [[Black triangle (UFO)|black triangle UFOs]].<ref name="auto1"/>

On December 1, 2009, the Ministry of Defence quietly closed down its UFO investigations unit. The unit's hotline and email address were suspended by the MoD on that date. The MoD said there was no value in continuing to receive and investigate sightings in a release, stating that "in over fifty years, no UFO report has revealed any evidence of a potential threat to the United Kingdom. The MoD has no specific capability for identifying the nature of such sightings. There is no Defence benefit in such investigation and it would be an inappropriate use of defence resources. Furthermore, responding to reported UFO sightings diverts MoD resources from tasks that are relevant to Defence." ''[[The Guardian]]'' reported that the MoD claimed the closure would save the Ministry around £50,000 a year. The MoD said it would continue to release UFO files to the public through The National Archives.<ref>{{cite news |title=Cost-cutting causes British gov't to shut down UFO investigations |first=Stephanie |last=Dearing |url=http://www.digitaljournal.com/article/283265 |work=Digital Journal |location=Toronto |date=December 5, 2009 |access-date=May 16, 2013 |archive-date=May 15, 2013 |archive-url=https://web.archive.org/web/20130515062510/http://www.digitaljournal.com/article/283265 |url-status=live }}</ref>

UFO reports, Parliamentary questions, and letters from members of the public were released on August 5, 2010, to the UK National Archives. "In one letter included in the files, a man alleges Churchill ordered a coverup of a WW II-era UFO encounter involving the Royal Air Force".<ref name="CBS1">{{cite web |last1=Binlot |first1=Ann |title=Winston Churchill Ordered UFO Coverup? |url=https://www.cbsnews.com/news/winston-churchill-ordered-ufo-coverup/ |website=cbsnews.com |date=August 5, 2010 |publisher=[[CBS news]] |access-date=November 10, 2021 |archive-date=November 10, 2021 |archive-url=https://web.archive.org/web/20211110142708/https://www.cbsnews.com/news/winston-churchill-ordered-ufo-coverup/ |url-status=live }}</ref><ref name="nationalarchivesUFO"/>

Reports of UFO sightings continue. According to ''[[The Independent]],'' there were 957 reported UFO sightings across the UK between January 2021 and May 2023, with [[Manchester]], [[London]], [[Liverpool]], and [[Glasgow]] being hotspots.<ref>{{Cite web |date=2023-10-24 |title=UFO hotspots revealed as ex Ministry of Defence expert calls for action |url=https://www.independent.co.uk/news/science/ufo-hotspots-revealed-aliens-b2434354.html |access-date=2023-11-16 |website=The Independent |language=en}}</ref>

==Studies==
Critics argue that all UFO evidence is anecdotal<ref name="Demon Haunted">{{cite book |last=Sagan |first=Carl |author-link=Carl Sagan |title=The Demon-Haunted World: Science as a Candle in the Dark |edition=1st |date=1995 |publisher=Random House |location=New York |isbn=0-394-53512-X |oclc=779687822 |lccn=95034076 |ref=Sagan 1995|title-link=The Demon-Haunted World }}</ref> and can be explained as prosaic natural phenomena. Defenders of UFO research counter that knowledge of observational data, other than what is reported in the popular media, is limited in the scientific community and further study is needed.<ref name="Revelations" /><ref name="FSS">[[#Friedman 2008|Friedman 2008]]</ref> Studies have established that the majority of UFO observations are misidentified conventional objects or natural phenomena—most commonly aircraft, balloons including [[sky lantern]]s, satellites, and astronomical objects such as [[meteors]],<!--No correction needed.--> bright stars and planets. A small percentage are [[hoax]]es.<ref group="note">For example, the USAF's [[Identification studies of UFOs|Project Blue Book]] concluded that less than 2% of reported UFOs were "psychological" or hoaxes; [[Allan Hendry]]'s study for CUFOS had less than 1%.</ref>

Fewer than 10% of reported sightings remain unexplained after proper investigation and therefore can be classified as unidentified in the strictest sense. According to [[Steven Novella]], proponents of the [[extraterrestrial hypothesis]] (ETH) suggest these unexplained reports are of alien spacecraft, however the [[null hypothesis]] cannot be excluded; that these reports are simply other more prosaic phenomena that cannot be identified due to lack of complete information or due to the necessary subjectivity of the reports. Novella says that instead of accepting the null hypothesis, UFO enthusiasts tend to engage in [[special pleading]] by offering outlandish, untested explanations for the validity of the ETH, which violate [[Occam's razor]].<ref>Novella, Steven, et al. ''The Skeptics' Guide to the Universe: How to Know What's Really Real in a World Increasingly Full of Fake''. Grand Central Publishing, 2018. pp. 160.</ref>

===Scientific===
{{Main|Ufology#Research}}
Historically, ufology has not been considered credible in mainstream science.<ref name=ufosociology /> The [[scientific community]] has generally deemed that UFO sightings are not worthy of serious investigation except as a cultural artifact.<ref>[[#Sagan & Page|Sagan & Page 1996]]</ref><ref name="McDonald">{{cite web |url=http://puhep1.princeton.edu/~mcdonald/JEMcDonald/mcdonald_hcsa_68.pdf |title=Statement on Unidentified Flying Objects: Submitted to the House Committee on Science and Astronautics at July 29, 1968, Symposium on Unidentified Flying Objects, Rayburn Bldg., Washington, D.C., by James E. McDonald |last=McDonald |first=James E. |author-link=James E. McDonald |date=July 29, 1968 |access-date=September 6, 2013 |archive-date=January 5, 2019 |archive-url=https://web.archive.org/web/20190105080523/http://puhep1.princeton.edu/~mcdonald/JEMcDonald/mcdonald_hcsa_68.pdf |url-status=dead }}</ref><ref name="COMETA">{{cite web |url=http://www.ufoevidence.org/topics/Cometa.htm |title=COMETA Report |publisher=ufoevidence.org |location=Seattle, WA |access-date=July 13, 2013 |archive-date=November 15, 2019 |archive-url=https://web.archive.org/web/20191115111528/http://www.ufoevidence.org/topics/Cometa.htm |url-status=live }}</ref><ref name="McCarthy">[[#McCarthy 1975|McCarthy 1975]]</ref><ref name="Sturrock/Stanford">{{cite web |url=http://news-service.stanford.edu/news/1998/july1/ufostudy71.html |title=UFO study causes media sensation: 7/1/98 |last=Salisbury |first=David F. |date=July 1, 1998 |work=Stanford Report |publisher=[[Stanford University]] |location=Stanford, CA |access-date=May 16, 2013 |archive-date=April 11, 2009 |archive-url=https://web.archive.org/web/20090411190007/http://news-service.stanford.edu/news/1998/july1/ufostudy71.html |url-status=live }}</ref><ref name="Menzel">[[#Menzel & Taves|Menzel & Taves 1977]]</ref><ref>{{cite news |title=UFO studies should be 'legitimate university subject', claims American professor |first=Andrew |last=Hough |url= https://www.telegraph.co.uk/news/newstopics/howaboutthat/ufo/7584331/UFO-studies-should-be-legitimate-university-subject-claims-American-professor.html |archive-url=https://ghostarchive.org/archive/20220111/https://www.telegraph.co.uk/news/newstopics/howaboutthat/ufo/7584331/UFO-studies-should-be-legitimate-university-subject-claims-American-professor.html |archive-date=January 11, 2022 |url-access=subscription |url-status=live |work=[[The Daily Telegraph]] |location=London |date=April 13, 2010 |access-date=July 13, 2013}}{{cbignore}}</ref>
[[Image:Allen Hynek Jacques Vallee 1.jpg|thumb|[[J. Allen Hynek|Allen Hynek]] (left) and [[Jacques Vallée]]]]
Studies of UFOs rarely appear in mainstream scientific literature. When asked, some scientists and scientific organizations have pointed to the end of official governmental studies in the U.S. in December 1969, following the statement by the government scientist [[Edward Condon]] that further study of UFOs could not be justified on grounds of scientific advancement.<ref name="COMETA"/><ref>[[#Swords & Powell|Swords & Powell 2012]], pp. 306–332</ref>

Nevertheless, on 14 September 2023, NASA reported the appointment, for the first time, of a Director of [[U.A.P.]] (known earlier as U.F.O.), identified as [[Mark McInerney]], to scientifically, and transparently, study such occurrences.<ref name="NYT-20230914">{{cite news |last=Chang |first=Kenneth |title=NASA Introduces New U.F.O. Research Director - The role was created in response to the recommendations of a report that found the agency could do more to collect and interpret data on unidentified anomalous phenomena. |url=https://www.nytimes.com/2023/09/14/science/nasa-ufo-uap-report.html |date=14 September 2023 |work=[[The New York Times]] |url-status=live |archive-url=https://archive.today/20230914235331/https://www.nytimes.com/2023/09/14/science/nasa-ufo-uap-report.html |archive-date=14 September 2023 |access-date=15 September 2023 }}</ref>

====Status as a pseudoscience====
{{Excerpt|Ufology|Status as a pseudoscience}}

[[Jacques Vallée]], a scientist and ufologist, claimed there were deficiencies in most UFO research, including government studies. He criticized the mythology and cultism often associated with UFO sightings, but despite the challenges, Vallée contended that several hundred professional scientists — a group both he and Hynek termed "the invisible college" — continued to study UFOs quietly on their own time.<ref name="Revelations" />

====Studies====
UFOs have become a prevalent theme in modern culture,<ref name="Revelations">[[#Vallée 2008|Vallée 2008]]</ref> and the social phenomena have been the subject of academic research in sociology and psychology.<ref name=ufosociology>{{cite journal |last=Cross |first=Anne |date=March 2004 |title=The Flexibility of Scientific Rhetoric: A Case Study of UFO Researchers |journal=[[Qualitative Sociology]] |publisher=[[Springer Science+Business Media|Springer]] |volume=27 |issue=1 |pages=3–34 |issn=0162-0436 |doi=10.1023/B:QUAS.0000015542.28438.41|s2cid=144197172 }}</ref>

{{Excerpt|Ufology|Current interest}}

====Sturrock panel categorization====

Besides anecdotal visual sightings, reports sometimes include claims of other kinds of evidence, including cases studied by the military and various government agencies of different countries (such as Project Blue Book, the Condon Committee, the French [[GEIPAN|GEPAN/SEPRA]], and Uruguay's current Air Force study).

A comprehensive scientific review of cases where physical evidence was available was carried out by the 1998 Sturrock panel, with specific examples of many of the categories listed below.
* Radar contact and tracking, sometimes from multiple sites. These have included military personnel and control tower operators, simultaneous visual sightings, and aircraft intercepts. One such example was the [[Belgian UFO wave|mass sightings]] of large, silent, low-flying black triangles in 1989 and 1990 over Belgium, tracked by [[NATO]] radar and jet interceptors, and investigated by Belgium's military (included photographic evidence). Another famous case from 1986 was the [[Japan Air Lines flight 1628 incident]] over [[Alaska]] investigated by the [[Federal Aviation Administration]] (FAA).
* Photographic evidence, including still photos, movie film, and video.
* Claims of physical trace of landing UFOs, including ground impressions, burned or desiccated soil, burned and broken foliage, magnetic anomalies{{Specify|date=February 2009}}, increased radiation levels, and metallic traces. (See, e.&nbsp;g. Height 611 UFO incident or the 1964 [[Lonnie Zamora incident|Lonnie Zamora]]'s [[Socorro, New Mexico]] encounter of the USAF Project Blue Book cases.) A well-known example from December 1980 was the USAF Rendlesham Forest incident in England. Another occurred in January 1981 in Trans-en-Provence and was investigated by GEPAN, then France's official government UFO-investigation agency. Project Blue Book head Edward J. Ruppelt described a classic 1952 CE2 case involving a patch of charred grass roots.
* Physiological effects on people and animals including temporary paralysis, skin burns and rashes, [[cornea]]l burns, and symptoms superficially resembling [[Acute radiation syndrome|radiation poisoning]], such as the [[Cash-Landrum incident]] in 1980.
* Animal/[[cattle mutilation]] cases, which some feel are also part of the UFO phenomenon.
* Biological effects on plants such as increased or decreased growth, germination effects on seeds, and blown-out stem nodes (usually associated with physical trace cases or [[crop circle]]s)
* [[Electromagnetic interference]] (<span class="ltr">EM</span>) effects. A famous [[1976 Tehran UFO incident|1976 military case]] over [[Tehran]], recorded in CIA and DIA classified documents, was associated with communication losses in multiple aircraft and weapons system failure in an [[McDonnell Douglas F-4 Phantom II|F-4 Phantom II]] jet interceptor as it was about to fire a missile on one of the UFOs.<ref>Fawcett & Greenwood, 81–89; [[#Good 1988|Good 1988]], pp. 318–322, 497–502</ref>
* Apparent remote radiation detection, some noted in FBI and CIA documents occurring over government nuclear installations at [[Los Alamos National Laboratory]] and [[Oak Ridge National Laboratory]] in 1950, also reported by Project Blue Book director Edward J. Ruppelt in his book.
* Claimed artifacts of UFOs themselves, such as 1957, [[Ubatuba]], Brazil, [[magnesium]] fragments analyzed by the [[Federal government of Brazil|Brazilian government]] and in the Condon Report and by others. The 1964 Lonnie Zamora incident also left metal traces, analyzed by NASA.<ref>[[#Good 1988|Good 1988]], pp. 371–373</ref><ref>[[#Stanford|Stanford 1976]], pp. 112–154</ref> A more recent example involves a teardrop-shaped object recovered by Bob White and was featured in a television episode of ''[[UFO Hunters]]''<ref>{{cite episode |title=UFO Relics |series=UFO Hunters |series-link=UFO Hunters |network=[[History (U.S. TV channel)|History]] |airdate=May 6, 2009 |season=3 |number=33}}</ref> but was later found to be accumulated waste metal residue from a grinding machine.<ref>Pat Linse, Ean Harrison (2011) [https://www.skeptic.com/eskeptic/11-10-12/#feature Bob White's Great UFO Artifact Mystery—Solved!] {{Webarchive|url=https://web.archive.org/web/20220429024657/https://www.skeptic.com/eskeptic/11-10-12/#feature |date=April 29, 2022 }} Skeptic magazine, Vol 16 No 3</ref>
* [[Angel hair (folklore)|Angel hair and angel grass]], possibly explained in some cases as nests from [[Ballooning (spider)|ballooning spiders]] or [[Chaff (radar countermeasure)|chaff]].<ref>{{Cite book|title=Heaven and hell : a compulsively readable compendium of myth, legend, wisdom, and wit for saints and sinners|date=2004|publisher=Atlantic Monthly Press|author=Faustino, Mara |isbn=0871136961|location=New York|oclc=55596198}}</ref>

====Scientific skepticism====

A [[scientifically skeptical]] group that has for many years offered critical analyses of UFO claims is the [[Committee for Skeptical Inquiry]] (CSI). One example is the response to local beliefs that "extraterrestrial beings" in UFOs were responsible for crop circles appearing in Indonesia, which the government and the [[National Institute of Aeronautics and Space]] (LAPAN) described as "man-made". Thomas Djamaluddin, research professor of astronomy and astrophysics at LAPAN stated: "We have come to agree that this 'thing' cannot be scientifically proven. Scientists have put UFOs in the category of [[pseudoscience]]."<ref name=Krismantari>{{cite news |title=Crop circles provide food for thought |first=Ika |last=Krismantari |url=http://thestar.com.my/news/story.asp?file=/2011/2/6/focus/7978671&sec=focus |work=[[The Star (Malaysia)|The Star]] |publisher=Star Publications |location=Petaling Jaya |date=February 6, 2011 |access-date=September 12, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20121030122405/http://thestar.com.my/news/story.asp?file=%2F2011%2F2%2F6%2Ffocus%2F7978671&sec=focus |archive-date=October 30, 2012  }}</ref>

===Governmental===
{{See also|Investigation of UFO reports by the United States government}}

[[File:CIA annotated drawing - dark grey solid looking UFO.webp|thumb|right|UFO drawing, authenticity unknown, attribution and date unspecified. One of hundreds of files resulting from US President [[Bill Clinton]]'s 1995 order to the [[CIA]] to declassify all documents with "historical value" that were at least 25 years old.]]
UFOs have been the subject of investigations by various governments that have provided extensive records related to the subject. Many of the most involved government-sponsored investigations ended after agencies concluded that there was no benefit to continued investigation.<ref>{{cite web|url=https://www.theguardian.com/world/2017/dec/17/pentagon-admits-running-secret-ufo-investigation-for-five-years|title=Pentagon admits running secret UFO investigation for five years|last=Siddique|first=Haroon|date=December 17, 2017|website=The Guardian|access-date=March 21, 2018|archive-date=April 25, 2020|archive-url=https://web.archive.org/web/20200425083827/https://www.theguardian.com/world/2017/dec/17/pentagon-admits-running-secret-ufo-investigation-for-five-years|url-status=live}}</ref><ref>{{Cite news|url=https://www.airspacemag.com/daily-planet/secret-government-program-track-ufos-its-not-first-180967597/|title=That Secret Government Program to Track UFOs? It's Not the First|last=Eghigian|first=Greg|work=Air & Space Magazine|access-date=March 21, 2018|archive-date=March 18, 2020|archive-url=https://web.archive.org/web/20200318015440/https://www.airspacemag.com/daily-planet/secret-government-program-track-ufos-its-not-first-180967597/|url-status=live}}</ref> These same negative conclusions also have been found in studies that were highly classified for many years, such as the UK's [[Flying Saucer Working Party]], [[Project Condign]], the U.S. CIA-sponsored Robertson Panel, the U.S. military investigation into the green fireballs from 1948 to 1951, and the Battelle Memorial Institute study for the USAF from 1952 to 1955 (Project Blue Book Special Report No. 14).

Some public government reports have acknowledged the possibility of the physical reality of UFOs, but have stopped short of proposing extraterrestrial origins, though not dismissing the possibility entirely. Examples are the Belgian military investigation into [[Belgian UFO wave|large triangles over their airspace]] in 1989–1991 and the 2009 [[Uruguayan Air Force]] study conclusion (see below).

====Claims by military, government, and aviation personnel====
In 2007, former [[Arizona]] governor [[Fife Symington]] claimed he had seen "a massive, delta-shaped craft silently navigate over Squaw Peak, a mountain range in Phoenix, Arizona" in 1997.<ref>{{cite news |last=Symington |first=Fife |author-link=Fife Symington |date=November 9, 2007 |title=Symington: I saw a UFO in the Arizona sky |url=http://edition.cnn.com/2007/TECH/science/11/09/simington.ufocommentary/ |work=[[CNN]] |publisher=[[Turner Broadcasting System]] |location=Atlanta, GA |access-date=November 25, 2013 |archive-date=October 20, 2013 |archive-url=https://web.archive.org/web/20131020025403/http://edition.cnn.com/2007/TECH/science/11/09/simington.ufocommentary/ |url-status=live }}</ref>
Apollo 14 astronaut [[Edgar Mitchell]] claimed he knew of senior government employees who had been involved in "close encounters", and because of this, he has no doubt that aliens have visited Earth.<ref>Mitchell, Edgar (2008), p262</ref>

In May 2019, ''The New York Times'' reported that American Navy fighter jets had several instances of unidentified instrumentation and tracking data while conducting exercises off the eastern seaboard of the United States from the summer of 2014 to March 2015. The ''Times'' published a cockpit instrument video that appeared to show an object moving at high speed near the ocean surface as it appeared to rotate, and objects that appeared capable of high acceleration, deceleration and maneuverability. In two separate incidents, a pilot reported his cockpit instruments locked onto and tracked objects but he was unable to see them through his helmet camera. In another encounter, flight instruments recorded an image described as a sphere encasing a cube between two jets as they flew about 100 feet apart.<ref name="NYT-20190526">{{cite news |last1=Cooper |first1=Helene |last2=Blumenthal |first2=Ralph |last3=Kean |first3=Leslie |title='Wow, What Is That?' Navy Pilots Report Unexplained Flying Objects |url=https://www.nytimes.com/2019/05/26/us/politics/ufo-sightings-navy-pilots.html |date=May 26, 2019 |work=[[The New York Times]] |access-date=May 27, 2019 |archive-date=February 26, 2020 |archive-url=https://web.archive.org/web/20200226005917/https://www.nytimes.com/2019/05/26/us/politics/ufo-sightings-navy-pilots.html |url-status=live }}</ref> The [[Pentagon UFO videos|Pentagon officially released these videos]] on April 27, 2020.<ref name="TheGuardian-20200527">{{cite news |last1=Strauss |first1=Daniel |title=Pentagon releases three UFO videos taken by US navy pilots |url=https://www.theguardian.com/world/2020/apr/27/pentagon-releases-three-ufo-videos-taken-by-us-navy-pilots |date=April 28, 2020 |work=[[The Guardian]] |access-date=May 10, 2020 |archive-date=May 9, 2020 |archive-url=https://web.archive.org/web/20200509210028/https://www.theguardian.com/world/2020/apr/27/pentagon-releases-three-ufo-videos-taken-by-us-navy-pilots |url-status=live }}</ref> The [[United States Navy]] has said there have been "a number of reports of unauthorized and/or unidentified aircraft entering various military-controlled ranges and designated air space in recent years".<ref name="edition.cnn.com">{{cite news |author=Chandelis Duster |title=Defense Department confirms leaked video of unidentified aerial phenomena is real |url=https://edition.cnn.com/2021/04/15/politics/unidentified-aerial-phenomena-defense-department/index.html |work=CNN |access-date=April 16, 2021 |archive-date=April 16, 2021 |archive-url=https://web.archive.org/web/20210416113817/https://edition.cnn.com/2021/04/15/politics/unidentified-aerial-phenomena-defense-department/index.html |url-status=live }}</ref>

In March 2021, news media announced a comprehensive report is to be compiled of UFO events accumulated by the [[United States]] over the years.<ref name="WP-20210323">{{cite news |last=Thebault |first=Reis |title=Thanks to Trump-era covid relief bill, a UFO report may soon be public — and it'll be big, ex-official says |url=https://www.washingtonpost.com/national-security/2021/03/23/ufo-report-covid-bill/ |date=March 23, 2021 |newspaper=[[The Washington Post]] |access-date=March 23, 2021 |archive-date=March 23, 2021 |archive-url=https://web.archive.org/web/20210323220342/https://www.washingtonpost.com/national-security/2021/03/23/ufo-report-covid-bill/ |url-status=live }}</ref>

On April 12, 2021, the Pentagon confirmed the authenticity of pictures and videos gathered by the [[Unidentified Aerial Phenomena Task Force]] (UAPTF), purportedly showing "pyramid shaped objects" hovering above the [[USS Russell (DDG-59)|USS Russell]] in 2019, off the coast of [[California]], with spokeswoman Susan Gough saying "I can confirm that the referenced photos and videos were taken by Navy personnel. The UAPTF has included these incidents in their ongoing examinations."<ref>{{cite news |title=Pentagon confirms leaked video of UFO 'buzzing' Navy warships is genuine |url=https://www.independent.co.uk/news/science/pentagon-ufo-navy-warship-video-b1830418.html |website=The Independent |language=en |date=April 13, 2021 |access-date=April 16, 2021 |archive-date=May 15, 2021 |archive-url=https://web.archive.org/web/20210515152258/https://www.independent.co.uk/news/science/pentagon-ufo-navy-warship-video-b1830418.html |url-status=live }}</ref><ref>{{cite news |title=Leaked footage shows UFOs flying around navy vessels |url=https://news.yahoo.com/leaked-footage-shows-uf-os-flying-around-navy-vessels-113812155.html?guccounter=1 |work=in.news.yahoo.com |access-date=April 16, 2021 |archive-date=April 16, 2021 |archive-url=https://web.archive.org/web/20210416055308/https://news.yahoo.com/leaked-footage-shows-uf-os-flying-around-navy-vessels-113812155.html?guccounter=1 |url-status=live }}</ref><ref>{{cite web |title=Pentagon Confirms That Leaked Video Is Part of UFO Investigation |url=https://futurism.com/leaked-video-unidentified-objects-swarming-navy-warship |website=Futurism |access-date=April 16, 2021 |archive-date=May 15, 2021 |archive-url=https://web.archive.org/web/20210515133753/https://futurism.com/leaked-video-unidentified-objects-swarming-navy-warship |url-status=live }}</ref><ref name="edition.cnn.com"/>

In May 2021, military pilots recalled their related encounters, along with camera and radar support, including one pilot's account noting that such incidents occurred "every day for at least a couple of years", according to an interview broadcast on the news program, ''[[60 Minutes]]'' (May 16, 2021).<ref name="WP-20210517">{{cite news |last=Thebault |first=Reis |title=For some Navy pilots, UFO sightings were an ordinary event: 'Every day for at least a couple years' |url=https://www.washingtonpost.com/nation/2021/05/17/ufo-sightings-navy-ryan-graves/ |date=May 17, 2021 |newspaper=[[The Washington Post]] |access-date=May 18, 2021 |archive-date=May 18, 2021 |archive-url=https://web.archive.org/web/20210518020102/https://www.washingtonpost.com/nation/2021/05/17/ufo-sightings-navy-ryan-graves/ |url-status=live }}</ref><ref>{{cite web |last1=video |title=Navy pilots describe encounters with UFOs |url=https://www.cbsnews.com/video/ufo-military-intelligence-video-60-minutes-2021-05-16/ |website=CBS News |access-date=May 19, 2021 |archive-date=May 19, 2021 |archive-url=https://web.archive.org/web/20210519001325/https://www.cbsnews.com/video/ufo-military-intelligence-video-60-minutes-2021-05-16/ |url-status=live }}</ref> Science writer and skeptic [[Mick West]] suggested the image was the result of an optical effect called a [[bokeh]] which can make out of focus light sources appear triangular or pyramidal due to the shape of the aperture of some lenses.<ref>{{cite web|title=Pentagon Confirms That Leaked Video Is Part of UFO Investigation|url=https://futurism.com/leaked-video-unidentified-objects-swarming-navy-warship|website=Futurism|access-date=April 16, 2021|archive-date=May 15, 2021|archive-url=https://web.archive.org/web/20210515133753/https://futurism.com/leaked-video-unidentified-objects-swarming-navy-warship|url-status=live}}</ref><ref name="newyorker">{{cite magazine |last1=Lewis-Kraus |first1=Gideon |title=How the Pentagon Started Taking U.F.O.s Seriously |url=https://www.newyorker.com/magazine/2021/05/10/how-the-pentagon-started-taking-ufos-seriously |magazine=The New Yorker |publisher=New Yorker Magazine |access-date=May 25, 2021}}</ref> In August, 2022, an article by West provided his detailed analysis of the video.<ref>West, Mick, ''[https://www.skeptic.com/reading_room/gimbal-video-genuine-ufo-or-camera-artifact/ The Gimbal Video: Genuine UFO or Camera Artifact?]'', ''[[Skeptic (American magazine)|Skeptic]]'', August 2, 2022</ref>
[[File:Prelimary-Assessment-UAP-20210625(<span class="ltr">1</span>).pdf|thumb|The 2021 [[Pentagon UFO Report]]]]
On June 25, 2021, U.S. Defense and [[United States Intelligence Community|intelligence]] officials released the nine pages [[Pentagon UFO Report]] (Preliminary Assessment: Unidentified Aerial Phenomena) on what they know about a series of unidentified flying objects that have been seen by American military pilots in the skies between 2004 and 2021.<ref>{{cite news |title=UFO report: US finds no explanation for sightings |url=https://www.bbc.com/news/world-us-canada-57619755 |work=BBC News |date=June 25, 2021 |access-date=July 4, 2021 |archive-date=July 6, 2021 |archive-url=https://web.archive.org/web/20210706173047/https://www.bbc.com/news/world-us-canada-57619755 |url-status=live }}</ref> <ref name=":1">{{Cite news |date=2021-06-26 |title=They're real, but are they alien? – key takeaways from the Pentagon report. Whatever the 'unidentified aerial phenomena' are, they are real objects that may pose a national security risk |url=https://www.theguardian.com/world/2021/jun/25/ufo-report-key-takeaways-us-government |access-date=2024-03-18 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref> The document refers to UAP rather than UFO.

The report does not mentions extraterrestrials, but instead warns of the phenomenon's potential threat to national security, which was the primary motive for writing the study. It concludes that the objects found by the US military appear to be real in the majority of the 144 occurrences documented. Only one of the cases described in the study was identified as a balloon.<ref name=":1"/>

"Most of the UAP reported probably do represent physical objects given that a majority of UAP were registered across multiple sensors, to include radar, infrared, electro-optical, weapon seekers, and visual observation", according to the report.<ref name=":1"/> The report also stated that "UAP probably lack a single explanation", and proposed five possible categories of explanation: airborne clutter, natural atmospheric phenomena, US government or industry development technology, foreign craft, and an "Other" category.<ref name="dni">{{cite web|author=<!--Not stated--> |date=25 June 2021 |title=Preliminary Assessment: Unidentified Aerial Phenomena |url=https://www.dni.gov/files/ODNI/documents/assessments/Prelimary-Assessment-UAP-20210625.pdf |url-status=live |archive-url=https://web.archive.org/web/20210726114054/https://www.dni.gov/files/ODNI/documents/assessments/Prelimary-Assessment-UAP-20210625.pdf |archive-date=26 July 2021 |access-date=26 June 2021 |website=[[Office of the Director of National Intelligence]]}}</ref>

Commenting on the document, [[NASA]] Administrator [[Bill Nelson]] said that he did not think we are alone, but the UFO sightings by pilots "may not be extraterrestrial."<ref>{{cite news |title=NASA administrator on UFO report: 'I don't think we are' alone |url=https://thehill.com/policy/national-security/560507-nasa-administrator-on-ufo-report-i-dont-think-we-are-alone |work=[[The Hill (newspaper)|The Hill]] |date=June 28, 2021 |access-date=July 3, 2021 |archive-date=July 3, 2021 |archive-url=https://web.archive.org/web/20210703164701/https://thehill.com/policy/national-security/560507-nasa-administrator-on-ufo-report-i-dont-think-we-are-alone |url-status=live }}</ref>

In December 2021, further official governmental investigations into UAPs and related, along with annual unclassified reports presented to Congress, have been authorized and funded.<ref name="LAT-20211216">{{cite news |last=Guthrie |first=Dillon |title=Op-Ed: OK! It's time to take UFOs seriously |url=https://www.latimes.com/opinion/story/2021-12-16/ufos-pentagon-congress-government |date=December 16, 2021 |work=[[Los Angeles Times]] |access-date=December 16, 2021 |archive-date=December 16, 2021 |archive-url=https://web.archive.org/web/20211216112423/https://www.latimes.com/opinion/story/2021-12-16/ufos-pentagon-congress-government |url-status=live }}</ref> Some have raised concerns about the new investigations.<ref name="NBC-20220108">{{cite news |last=Seitz-Wald |first=Alex |title=Disclosure or deception? New UFO Pentagon office divides believers - The U.S. government hasn't comprehensively studied UFOs in decades — but not all ufologists are excited about a new Pentagon investigative office. |url=https://www.nbcnews.com/politics/national-security/disclosure-or-deception-new-ufo-pentagon-office-divides-believers-n1287199 |date=January 8, 2022 |work=[[NBC News]] |access-date=January 9, 2022 |archive-date=January 8, 2022 |archive-url=https://web.archive.org/web/20220108235315/https://www.nbcnews.com/politics/national-security/disclosure-or-deception-new-ufo-pentagon-office-divides-believers-n1287199 |url-status=live }}</ref>

==== Conspiracy theories ====

{{See also|UFO conspiracy theory|Steven M. Greer|Men in black| Brookings Report}}
UFOs are sometimes an element of conspiracy theories in which governments are allegedly intentionally "covering up" the existence of aliens by removing physical evidence of their presence or even collaborating with extraterrestrial beings. There are many versions of this story; some are exclusive, while others overlap with various other conspiracy theories.

In the U.S., an opinion poll conducted in 1997 suggested that 80% of Americans believed the U.S. government was withholding such information.<ref>{{cite press release |title=Is the Government Hiding Facts On UFOs & Extraterrestrial Life?; New Roper Poll Reveals that More Than Two-Thirds of Americans Think So |date=October 15, 2002 |publisher=[[Business Wire]] |location=New York |url=http://www.thefreelibrary.com/Is+the+Government+Hiding+Facts+On+UFOs+%26+Extraterrestrial+Life%3F%3B+New...-a092843602 |access-date=September 12, 2013}}</ref><ref name="cnn97">{{cite news |title=Poll: U.S. hiding knowledge of aliens |url=http://www.cnn.com/US/9706/15/ufo.poll/index.html |work=CNN |publisher=Turner Broadcasting System |location=Atlanta, GA |date=June 15, 1997 |access-date=September 12, 2013 |archive-date=October 17, 2013 |archive-url=https://web.archive.org/web/20131017204345/http://www.cnn.com/US/9706/15/ufo.poll/index.html |url-status=live }}</ref> Various notables have also expressed such views. Some examples are astronauts Gordon Cooper and Edgar Mitchell, Senator [[Barry Goldwater]], Vice Admiral [[Roscoe H. Hillenkoetter]] (the first CIA director), [[Peter Hill-Norton, Baron Hill-Norton|Lord Hill-Norton]] (former British Chief of Defense Staff and NATO head), the 1999 French COMETA study by various French generals and aerospace experts, and [[Yves Sillard]] (former director of CNES, new director of French UFO research organization GEIPAN).<ref name="geipan" />

In June 2023, United States Air Force officer and former intelligence official [[David Grusch UFO whistleblower claims|David Grusch]] claimed that the U.S. federal government has maintained a highly secretive UFO retrieval program since the 1940s and that the government possesses multiple spacecraft of "non-human" origin.<ref name="entin">{{cite web |last=Entin |first=Brian |date=5 June 2023 |title=Military whistleblower claims US has UFO retrieval program |url=https://www.newsnationnow.com/space/military-whistleblowe-us-ufo-retrieval-program/ |access-date=6 June 2023 |website=NewsNation |archive-date=June 6, 2023 |archive-url=https://web.archive.org/web/20230606144841/https://www.newsnationnow.com/space/military-whistleblowe-us-ufo-retrieval-program/ |url-status=live }}</ref><ref>{{cite web |last=Wallace |first=Danielle |date=6 June 2023 |title=Military whistleblower goes public with claims US has secret UFO retrieval program: 'Terrestrial arms race' |url=https://www.foxnews.com/politics/military-whistleblower-public-claims-us-secret-ufo-retrieval-program-terrestrial-arms-race |access-date=6 June 2023 |website=Fox News |archive-date=June 6, 2023 |archive-url=https://web.archive.org/web/20230606212634/https://www.foxnews.com/politics/military-whistleblower-public-claims-us-secret-ufo-retrieval-program-terrestrial-arms-race |url-status=live }}</ref><ref>{{cite web |last=Coen |first=Susie |date=7 June 2023 |title='Non-human spacecraft' found by US 'for decades' |url=https://www.telegraph.co.uk/world-news/2023/06/07/ufos-made-with-non-human-materials-found-by-us/ |access-date=9 June 2023 |website=The Telegraph |archive-date=June 10, 2023 |archive-url=https://web.archive.org/web/20230610035130/https://www.telegraph.co.uk/world-news/2023/06/07/ufos-made-with-non-human-materials-found-by-us/ |url-status=live }}</ref><ref name="gab9">{{cite web |last=Gabbatt |first=Adam |date=9 June 2023 |title=A whistleblower claims the US has alien vehicles. But where's the proof? |url=https://www.theguardian.com/us-news/2023/jun/09/ufo-alien-vehicles-us-whistleblower-evidence-where-is-proof |access-date=9 June 2023 |work=The Guardian |archive-date=June 10, 2023 |archive-url=https://web.archive.org/web/20230610032500/https://www.theguardian.com/us-news/2023/jun/09/ufo-alien-vehicles-us-whistleblower-evidence-where-is-proof |url-status=live }}</ref>

===== "Disclosure" advocates =====
In May 2001, a press conference was held at the [[National Press Club (United States)|National Press Club]] in [[Washington, D.C.]], by an organization called the [[Steven M. Greer|Disclosure Project]], featuring twenty persons including retired Air Force and FAA personnel, intelligence officers and an air traffic controller.<ref>{{YouTube|id=K5Mv0_RFEB8|title="2001 National Press Club Event"|link=no}}</ref><ref>{{cite news |title=Government is covering up UFO evidence, group says |first=Julia |last=Duin |url=http://www.washingtontimes.com/news/2001/may/11/20010511-022955-2774r/ |newspaper=[[The Washington Times]] |publisher=[[News World Communications]] |location=Washington, D.C. |date=May 11, 2001 |access-date=September 11, 2013 |archive-date=January 19, 2016 |archive-url=https://web.archive.org/web/20160119203739/http://www.washingtontimes.com/news/2001/may/11/20010511-022955-2774r/ |url-status=live }}</ref><ref>{{cite news |title=They're Here; UFO Watchers to Reveal Proof That Aliens Have Visited Earth |first=Vicky |last=Spavin |url=http://www.thefreelibrary.com/They%27re+Here%3B+UFO+watchers+to+reveal+proof+that+aliens+have+visited...-a074321804 |work=[[Daily Record (Scotland)|The Daily Record]] |publisher=[[Trinity Mirror]] |location=Glasgow |date=May 9, 2001 |access-date=March 10, 2013 |archive-date=March 5, 2016 |archive-url=https://web.archive.org/web/20160305060038/http://www.thefreelibrary.com/They%27re+Here%3B+UFO+watchers+to+reveal+proof+that+aliens+have+visited...-a074321804 |url-status=live }}</ref><ref>{{cite news |title=Group Calls for Disclosure of UFO Info |first1=Katelynn |last1=Raymer |first2=David |last2=Ruppe |url=https://abcnews.go.com/Technology/story?id=98572 |work=[[ABC News]] |date=May 10, 2001 |access-date=March 11, 2013 |archive-date=July 28, 2013 |archive-url=https://web.archive.org/web/20130728235120/http://abcnews.go.com/Technology/story?id=98572 |url-status=live }}</ref><ref>{{cite news |title=UFO spotters slam 'US cover-up' |first=Rob |last=Watson |url=http://news.bbc.co.uk/2/hi/americas/1322432.stm |work=BBC News |publisher=BBC |location=London |date=May 10, 2001 |access-date=September 11, 2013 |archive-date=July 23, 2019 |archive-url=https://web.archive.org/web/20190723074515/http://news.bbc.co.uk/2/hi/americas/1322432.stm |url-status=live }}</ref><ref>{{cite news |title=Men in Suits See Aliens as Part of Solution, Not Problem |first=Sharon |last=Kehnemui |url=http://www.foxnews.com/story/0,2933,24364,00.html |work=FoxNews.com |publisher=Fox Entertainment Group |location=New York |date=May 10, 2001 |access-date=May 10, 2007 |archive-date=August 25, 2013 |archive-url=https://web.archive.org/web/20130825092411/http://www.foxnews.com/story/0,2933,24364,00.html |url-status=live }}</ref><ref>{{cite news |title=Ooo-WEE-ooo Fans Come to D.C. |first=Declan |last=McCullagh |author-link=Declan McCullagh |url=https://www.wired.com/culture/lifestyle/news/2001/05/43526 |work=[[Wired (website)|Wired News]] |publisher=[[Lycos]] |location=Waltham, MA |date=May 10, 2001 |access-date=May 10, 2007 |archive-date=June 9, 2008 |archive-url=https://web.archive.org/web/20080609085452/http://www.wired.com/culture/lifestyle/news/2001/05/43526 |url-status=live }}</ref> They all gave a brief account of their claims that evidence of UFOs was being suppressed and said they would be willing to testify under oath to a Congressional committee. According to a 2002 report in the [[Daily Emerald|Oregon ''Daily Emerald'']], Disclosure Project founder [[Steven M. Greer]] is an "alien theorist" who claims "proof of government coverup" consisting of 120 hours of testimony from various government officials on the topic of UFOs, including astronaut [[Gordon Cooper]].<ref>{{cite news |title=Alien theorist offers proof of government coverup |first=Brad |last=Schmidt |url=http://dailyemerald.com/2002/04/25/alien-theorist-offers-proof-of-government-coverup/ |newspaper=[[Daily Emerald|Oregon Daily Emerald]] |location=Eugene, OR |date=April 25, 2002 |access-date=December 12, 2012 |archive-date=August 14, 2012 |archive-url=https://web.archive.org/web/20120814040025/http://dailyemerald.com/2002/04/25/alien-theorist-offers-proof-of-government-coverup/ |url-status=live }}</ref>

In 2007, the German UFO conspiracy forum [[Disclose.tv]] was created. The website's name references the concept of disclosure.<ref name=":0">{{Cite web |last1=Thomas |first1=W. F. |date=12 January 2022 |title=Disclose.tv: Conspiracy Forum Turned Disinformation Factory |url=https://www.logically.ai/articles/disclose.tv-conspiracy-forum-turned-disinformation-factory |url-status=live |archive-url=https://web.archive.org/web/20220112153617/https://www.logically.ai/articles/disclose.tv-conspiracy-forum-turned-disinformation-factory |archive-date=12 January 2022 |access-date=2022-10-26 |website=[[Logically (company)|Logically]] |language=en |quote=The name "Disclose" references the concept within UFO enthusiast circles of "disclosure," the time when the government will confirm the existence of aliens and release information regarding them.}}</ref>

On September 27, 2010, a group of six former USAF officers and one former enlisted Air Force man held a press conference at the National Press Club in Washington, D.C., on the theme "U.S. Nuclear Weapons Have Been Compromised by Unidentified Aerial Objects"<ref>{{cite press release |last1=Salas |first1=Robert |last2=Hastings |first2=Robert |title=U.S. Nuclear Weapons Have Been Compromised by Unidentified Aerial Objects |date=September 15, 2010 |publisher=[[PR Newswire]] |location=Washington, D.C. |url=https://www.reuters.com/article/idUS166901+15-Sep-2010+PRN20100915 |access-date=September 11, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20110127022656/http://www.reuters.com/article/idUS166901+15-Sep-2010+PRN20100915 |archive-date=January 27, 2011  }} {{YouTube|id=lR3Fhyi14Pw|title="National Press Club: UFOs Tampering with Nukes - Part 1/7"|link=no}}</ref> in which they claimed they had witnessed UFOs hovering near missile sites and even disarming the missiles.

From April 29 to May 3, 2013, the Paradigm Research Group held the "Citizen Hearing on Disclosure" at the National Press Club. The group paid former U.S. Senator [[Mike Gravel]] and former Representatives [[Carolyn Cheeks Kilpatrick]], [[Roscoe Bartlett]], [[Merrill Cook]], [[Darlene Hooley]], and [[Lynn Woolsey]] $20,000 each to hear testimony from a panel of researchers which included witnesses from military, agency, and political backgrounds.<ref>{{cite news |title=Ex-Rep. Kilpatrick 'waiting to hear' evidence of space aliens |first=Marisa |last=Schultz |url=http://www.detroitnews.com/article/20130429/POLITICS03/304290397 |work=[[The Detroit News]] |publisher=[[Digital First Media|MediaNews Group]] |date=April 29, 2013 |access-date=September 11, 2013 |archive-url=https://web.archive.org/web/20130531170741/http://www.detroitnews.com/article/20130429/POLITICS03/304290397 |archive-date=May 31, 2013}}</ref><ref>{{cite web |url=http://www.citizenhearing.org/ |title=Citizen Hearing on Disclosure |website=Citizen Hearing on Disclosure |publisher=Paradigm Research Group |location=Bethesda, MD |access-date=September 11, 2013 |archive-date=September 15, 2013 |archive-url=https://web.archive.org/web/20130915073916/http://www.citizenhearing.org/ |url-status=live }}</ref>

===Fringe===
The void left by the lack of institutional or scientific study has given rise to independent researchers and fringe groups, including the [[National Investigations Committee on Aerial Phenomena]] (NICAP) in the mid-20th century and, more recently, the [[Mutual UFO Network]] (MUFON)<ref>{{cite web |url=http://www.mufon.com/ |title=Mutual UFO Network |website=MUFON.com |publisher=[[Mutual UFO Network|Mutual UFO Network, Inc.]] |location=Cincinnati, OH |access-date=July 13, 2013 |archive-date=December 21, 1997 |archive-url=https://web.archive.org/web/19971221203858/http://mufon.com/ |url-status=live }}</ref> and the [[Center for UFO Studies]] (CUFOS).<ref>{{cite web |url=http://www.cufos.org/org.html |title=Center for UFO Studies |website=CUFOS.org |publisher=[[Center for UFO Studies]] |location=Chicago |access-date=July 13, 2013 |archive-date=October 21, 1997 |archive-url=https://web.archive.org/web/19971021071948/http://www.cufos.org/org.html |url-status=live }}</ref> The term "[[Ufology]]" is used to describe the collective efforts of those who study reports and associated evidence of unidentified flying objects.<ref>{{cite news |title=UFO Sightings Increase 67 Percent In 3 Years, History Channel Investigates Unexplained Aerial Phenomena |first=Lee |last=Speigel |url=http://www.huffingtonpost.com/2011/08/26/ufos-pilots-history-channel_n_935847.html |work=[[The Huffington Post]] |publisher=[[AOL]] |date=August 26, 2011 |access-date=July 13, 2013 |archive-date=September 9, 2013 |archive-url=https://web.archive.org/web/20130909064325/http://www.huffingtonpost.com/2011/08/26/ufos-pilots-history-channel_n_935847.html |url-status=live }}</ref>

===Private===
Some private studies have been neutral in their conclusions but argued that the inexplicable core cases call for continued scientific study. Examples are the Sturrock panel study of 1998 and the 1970 AIAA review of the Condon Report.

=== Religious ===
UFOs have been interpreted by some groups in a religious way, often influenced by the [[Theosophy|Theosophical]] tradition. Some Christians have interpreted UFOs as [[Demon|demonic]] entities.<ref>{{Cite journal |last=Partridge |first=Christopher |date=July 2004 |title=Alien demonology: The Christian roots of the malevolent extraterrestrial in UFO religions and abduction spiritualities |url=http://www.tandfonline.com/doi/abs/10.1016/j.religion.2004.04.014 |journal=Religion |language=en |volume=34 |issue=3 |pages=163–189 |doi=10.1016/j.religion.2004.04.014 |issn=0048-721X}}</ref>

===Ufology===

{{Main|Ufology}}
[[File:Close up of light in sky, Sri Lanka.jpg|thumb|alt=Swirling multicolored cloud like object in the sky|A photograph of an unusual atmospheric occurrence observed over Sri Lanka, forwarded to the UK [[Ministry of Defence (United Kingdom)|Ministry of Defence]] by RAF Fylingdales, 2004]]

''Ufology'' is a [[neologism]] describing the collective efforts of those who study UFO reports and associated evidence.

====Researchers====

{{Main|List of ufologists}}

====Sightings====

{{Main|List of reported UFO sightings}}

====Organizations====

{{Main|List of UFO organizations}}

==In popular culture==

{{Main|UFOs in fiction}}
[[File:Tenjo Estatua UFO.JPG|thumb|right|An UFO monument in [[Tenjo]], [[Colombia]]]]

UFOs have constituted a widespread international [[cultural phenomenon]] since the 1950s. [[Gallup (company)|Gallup Polls]] rank UFOs near the top of lists for subjects of widespread recognition. In 1973, a survey found that 95 percent of the public reported having heard of UFOs, whereas only 92 percent had heard of [[President of the United States|U.S. President]] [[Gerald Ford]] in a 1977 poll taken just nine months after he left the White House.<ref>[[#Jacobs|Jacobs 2000]], Chapter: "UFOs: Lost in the Myths" by Thomas E. Bullard, p. 141</ref><ref>[[#Jacobs|Jacobs 2000]], Chapter: "UFOs, the Military, and the Early Cold War Era" by [[Michael D. Swords]], pp. 82–121</ref>

A 1996 Gallup Poll reported that 71 percent of the United States population believed the U.S. government was covering up information regarding UFOs. A 2002 [[Elmo Roper|Roper Poll]] for the [[Syfy|Sci-Fi Channel]] found similar results, but with more people believing UFOs are extraterrestrial craft. In that latest poll, 56 percent thought UFOs were real craft and 48 percent that aliens had visited the Earth. Again, about 70 percent felt the government was not sharing everything it knew about UFOs or extraterrestrial life.<ref>{{cite web |url=http://www.scifi.com/ufo/roper/ |title=The Roper Poll |work=Ufology Resource Center |publisher=[[Syfy|SciFi.com]] |date=September 2002 |archive-url=https://web.archive.org/web/20060713204836/http://www.scifi.com/ufo/roper/ <!--Bot retrieved archive--> |archive-date=July 13, 2006 |access-date=August 19, 2006}}</ref><ref>{{cite web |url=http://www.mufon.com/fastfacts.htm |title=UFO Fast Facts |website=MUFON.com |publisher=Mutual UFO Network, Inc. |location=Cincinnati, OH |archive-url=https://web.archive.org/web/20080430100715/http://www.mufon.com/fastfacts.htm |archive-date=April 30, 2008 |access-date=July 13, 2013}}</ref>

Another effect of the flying saucer type of UFO sightings has been Earth-made flying saucer craft in space fiction, for example the United Planets Cruiser [[C-57D|C57D]] in ''[[Forbidden Planet]]'' (1956), the ''[[Jupiter 2|Jupiter{{nbsp}}2]]''<!--No correction needed.--> in ''[[Lost in Space]]'', and the saucer section of the [[Starship Enterprise|USS ''Enterprise'']] in ''[[Star Trek]]''. UFOs and [[extraterrestrials]] have been featured [[List of films featuring extraterrestrials|in many movies]].

The intense secrecy surrounding the secret Nevada base, known as [[Area 51]], has made it the frequent subject of conspiracy theories and a central component of UFO folklore. In July 2019, more than 2 million people responded to a [[Storm Area 51|joke proposal to storm Area 51]] which appeared in an anonymous Facebook post.<ref>{{cite news|url=https://www.independent.co.uk/life-style/gadgets-and-tech/news/storm-area-51-when-where-aliens-military-base-raid-facebook-event-a9005546.html|title=Storm Area 51: Are Alien-hunters Really Planning to 'Raid' the Secret U.S. Military Base?|first=Andrew|last=Griffin|newspaper=The Independent|date=July 17, 2019|access-date=July 3, 2021|archive-date=July 16, 2019|archive-url=https://web.archive.org/web/20190716140827/https://www.independent.co.uk/life-style/gadgets-and-tech/news/storm-area-51-when-where-aliens-military-base-raid-facebook-event-a9005546.html|url-status=live}}</ref> Two music festivals in rural Nevada, "AlienStock" and "Storm Area 51 Basecamp", were subsequently organized to capitalize on the popularity of the original Facebook event.<ref>{{Cite news|url=https://www.reuters.com/article/us-usa-area51/in-nevada-desert-area-51-raid-lures-festive-ufo-hunters-three-arrested-idUSKBN1W51H6|title=Area 51 raid lures festive UFO hunters to Nevada desert; five arrested|last=Richwine|first=Lisa|date=September 20, 2019|work=Reuters|access-date=July 3, 2021|archive-date=November 23, 2020|archive-url=https://web.archive.org/web/20201123210209/https://www.reuters.com/article/us-usa-area51/in-nevada-desert-area-51-raid-lures-festive-ufo-hunters-three-arrested-idUSKBN1W51H6|url-status=live}}</ref>

==Notes==

{{Notelist}}
{{Reflist|group="note"}}

==References==

{{Reflist|30em}}

==Bibliography==
===General===
{{refbegin|30em}}
* Bullard, Thomas; (2012). ''The Myth and Mystery of UFOs''. Lawrence: University of Kansas. {{ISBN|978-0-7006-1729-6}}.
* {{cite book |last=Clark |first=Jerome |author-link=Jerome Clark |title=The UFO Book: Encyclopedia of the Extraterrestrial |date=1998 |publisher=[[Visible Ink Press]] |location=Detroit, MI |isbn=1-57859-029-9 |oclc=37370629 |lccn=97035767 |ref=Clark |url=https://archive.org/details/ufobookencyclope0000clar }} Many classic cases and UFO history provided in great detail; highly documented.
* {{cite book |last=Curran |first=Douglas |others=Foreword by [[Tom Wolfe]] |title=In Advance of the Landing: Folk Concepts of Outer Space |edition=Revised |orig-year=1st edition originally published 1985; New York: [[Abbeville Publishing Group|Abbeville Press]] |date=2001 |publisher=Abbeville Press |location=New York |isbn=0-7892-0708-7 |oclc=45270419 |lccn=00052589 |ref=Curran}} Non-sensational but fair treatment of contemporary UFO legend and lore in N. America, including the so-called "contactee cults". The author traveled the United States with his camera and tape recorder and directly interviewed many individuals.
* {{cite journal |last1=Deardorff |first1=J. |last2=Haisch |first2=B. |author-link2=Bernard Haisch |last3=Maccabee |first3=B. |author-link3=Bruce Maccabee |last4=Puthoff |first4=H. E. |author-link4=Harold E. Puthoff |date=2005 |title=Inflation-Theory Implications for Extraterrestrial Visitation |journal=[[Journal of the British Interplanetary Society]] |volume=58 |pages=43–50 |location=London |publisher=[[British Interplanetary Society]] |issn=0007-084X |bibcode=2005JBIS...58...43D |url=https://www.researchgate.net/publication/238693432 |access-date=September 21, 2018 }}
* {{cite book |last=Friedman |first=Stanton T. |author-link=Stanton T. Friedman |title=Flying Saucers and Science: A Scientist Investigates the Mysteries of UFOs |date=2008 |publisher=New Page Books |location=Franklin Lakes, NJ |isbn=978-1-60163-011-7 |oclc=179812690 |lccn=2008006291 |ref=Friedman 2008}}
* Greer, Steven M.; (2001). ''Disclosure''. Crozer: Crossing Point. {{ISBN|0-9673238-1-9}}.
* {{cite book |editor-last=Hall |editor-first=Richard H. |editor-link=Richard H. Hall |title=The UFO Evidence |edition=Reissue |orig-year=Originally published 1964; Washington, D.C.: [[National Investigations Committee On Aerial Phenomena]] (NICAP) |date=1997 |publisher=[[Barnes & Noble Books#Publishing|Barnes & Noble Books]] |location=New York |isbn=0-7607-0627-1 |oclc=39544334 |lccn=64006912 |ref=Hall 1997}} Well-organized, exhaustive summary and analysis of 746 unexplained NICAP cases out of 5000 total cases—a classic.
* {{cite book |editor-last=Hall |editor-first=Richard H. |title=UFO Evidence: Volume II, A 30-year Report |year=2001 |publisher=[[Rowman & Littlefield|Scarecrow Press]] |location=Lanham, MD |isbn=0-8108-3881-8 |oclc=44391782 |lccn=00055624 |ref=Hall 2001}} Another exhaustive case study, more recent UFO reports.
* {{cite book |last=Hendry |first=Allan |author-link=Allan Hendry |others=Foreword by [[J. Allen Hynek]] |title=The UFO Handbook: A Guide to Investigating, Evaluating, and Reporting UFO Sightings |edition=1st |date=1979 |publisher=[[Doubleday (publisher)|Doubleday]] |location=Garden City, NY |isbn=0-385-14348-6 |oclc=4642190 |lccn=78008211 |ref=Hendry}} Skeptical but balanced analysis of 1300 CUFOS UFO cases.
* {{cite book |last=Hynek |first=J. Allen |author-link=J. Allen Hynek |title=The UFO Experience: A Scientific Inquiry |url=https://archive.org/details/ufoexperience00jall |url-access=registration |date=1972 |publisher=[[Regnery Publishing#Henry Regnery Company|Henry Regnery Company]] |location=Chicago |oclc=341112 |lccn=76183827 |ref=Hynek 1972 }}
* {{cite book |last=Hynek |first=J. Allen |others=New foreword by [[Jacques Vallée]] |title=The Hynek UFO Report |orig-year=Originally published 1977; New York: [[Dell Publishing|Dell Publishing Company]] |date=1997 |publisher=Barnes & Noble Books |location=New York |isbn=0-7607-0429-5 |oclc=3601609 |ref=Hynek 1997}} Analysis of 640 high-quality cases through 1969 by UFO legend Hynek.
* {{cite book |editor-last=Jacobs |editor-first=David M. |editor-link=David M. Jacobs |title=UFOs and Abductions: Challenging the Borders of Knowledge |date=2000 |publisher=[[University Press of Kansas]] |location=Lawrence, KS |isbn=0-7006-1032-4 |oclc=43615835 |lccn=00028970 |ref=Jacobs |url=https://archive.org/details/ufosabductions00davi }}
* {{cite book |last=Kean |first=Leslie |author-link= Leslie Kean|title=UFOs: Generals, Pilots and Government Officials Go on the Record |date=2010 |publisher= Harmony Books }}
* {{cite book |publisher = Éd. Sainte Jeanne d'Arc |isbn = 978-2-9504914-8-0 |last = Kérizo, Alain |title = Les OVNI identifiés: les extraterrestres dans le mystère d'iniquité |url = https://books.google.com/books?id=cOuXGQAACAAJ |location = Villegenon |date = 1997 |oclc = 465784973 |language = fr }} ([http://www.angelusonline.org/index.php?section=articles&subsection=show_article&article_id=2102 associated article] {{Webarchive|url=https://web.archive.org/web/20150412034718/http://www.angelusonline.org/index.php?section=articles&subsection=show_article&article_id=2102 |date=April 12, 2015 }})
* {{cite book |last=Keyhoe |first=Donald |author-link=Donald Keyhoe |title=The Flying Saucers are Real |url=http://www.nicap.org/fsar/fsar-chapters.htm |access-date=September 6, 2013 |date=1950 |publisher=[[Fawcett Publications]] |location=New York |oclc=1674240 |lccn=50004886 |ref=Keyhoe 1950 |archive-date=September 6, 2013 |archive-url=https://web.archive.org/web/20130906214600/http://www.nicap.org/fsar/fsar-chapters.htm |url-status=live }}
* {{cite book |last=Keyhoe |first=Donald E. |title=Flying Saucers from Outer Space |url=http://www.nicap.org/books/fsos/fsos.htm |access-date=May 16, 2013 |edition=1st |date=1953 |publisher=[[Henry Holt and Company]] |location=New York |oclc=181368 |lccn=53009588 |ref=Keyhoe 1953 |archive-date=May 14, 2013 |archive-url=https://web.archive.org/web/20130514145116/http://www.nicap.org/books/fsos/fsos.htm |url-status=live }}
* {{cite book |last=Latagliata |first=Rosamaria |title=UFO: verità o menzogna? |series=Gli atlanti di Voyager |date=2006 |publisher=Giunti Editore |location=Florence |language=it |isbn=978-88-09-04698-6 |oclc=635701671 |ref=Latagliata}}
* {{cite book |last=McCarthy |first=Paul E. |title=Politicking and Paradigm Shifting: James E. McDonald and the UFO Case Study |url=http://www.project1947.com/shg/mccarthy/shgintro.html |access-date=July 13, 2013 |type=Thesis/dissertation |edition=Internet |date=1975 |publisher=Sign Historical Group |location=Canterbury, CT |oclc=663722044 |ref=McCarthy 1975 |archive-date=September 10, 2012 |archive-url=https://web.archive.org/web/20120910051428/http://www.project1947.com/shg/mccarthy/shgintro.html |url-status=live }}
* {{cite book |last1=Menzel |first1=Donald H. |author-link1=Donald Howard Menzel |last2=Taves |first2=Ernest H. |others=Introduction by [[Fred Lawrence Whipple|Fred L. Whipple]] |title=The UFO Enigma: The Definitive Explanation of the UFO Phenomenon |url=https://archive.org/details/ufoenigmadefinit0000menz |url-access=registration |edition=1st |date=1977 |publisher=Doubleday |location=Garden City, NY |isbn=0-385-03596-9 |oclc=2597609 |lccn=76016255 |ref=Menzel & Taves }}
* Mitchell, Edgar; (2008). ''The Way of the Explorer''. Franklin Lakes: Career Press. {{ISBN|978-1-56414-977-0}}.
* Office of the Director of National Intelligence (USA); (2021). ''Preliminary Assessment: Unidentified Aerial Phenomena''
* {{cite news
|title=Reasons to Believe (a collection of short articles by nine different authors)
|newspaper=[[New York (magazine)|New York]]
|date=April 1, 2018
|pages=25–33}}
* {{cite book |last1=Rose |first1=Bill |last2=Buttler |first2=Tony |title=Flying Saucer Aircraft |series=Secret Projects |date=2004 | publisher=[[Ian Allan Publishing|Midland Publishing]] |location=Hinckley, England |isbn=978-1-85780-233-7 |oclc=99774524 |ref=Rose & Buttler}}
* {{cite book |title=UFO's: A Scientific Debate |editor1-last=Sagan |editor1-first=Carl |editor1-link=Carl Sagan |editor2-last=Page |editor2-first=Thornton |edition=Reprint |orig-year=Originally published 1972 |date=1996 |publisher=[[Barnes & Noble Classics Collection|Barnes & Noble]]<!--No correction needed.--> |location=New York |isbn=978-0-7607-0196-6 |oclc=35840064 |lccn=72004572 |ref=Sagan & Page}}
* {{cite book |last=Scully |first=Frank |author-link=Frank Scully |title=Behind the Flying Saucers |url=https://archive.org/details/behindflyingsauc00scul |url-access=registration |date=1950 |publisher=Henry Holt and Company |location=New York |oclc=1467735 |ref=Scully }}
* {{cite book |last=Sheaffer |first=Robert |author-link=Robert Sheaffer |title=The UFO Verdict: Examining the Evidence |date=1981 |publisher=[[Prometheus Books]] |location=Buffalo, NY |isbn=0-87975-146-0 |oclc=7364885 |lccn=80084406 |ref=Scheaffer 1981}}
* {{cite book |last=Sheaffer |first=Robert |title=UFO Sightings: The Evidence |date=1998 |publisher=Prometheus Books |location=Amherst, NY |isbn=1-57392-213-7 |oclc=38738821 |lccn=98006410 |ref=Scheaffer 1998}} Revised edition of ''The UFO Verdict''.
* {{cite book |last=Stanford |first=Ray |title=Socorro 'Saucer' in a Pentagon Pantry |edition=1st |date=1976 |publisher=Blueapple Books |location=Austin, TX |isbn=0-917092-00-7 |oclc=2524239 |lccn=76013768 |ref=Stanford}}
* {{cite journal |last1=Sturrock |first1=Peter A. |author-link1=Peter A. Sturrock |last2=Holzer |first2=T. E. |last3=Jahn |first3=R. |last4=Pritchard |first4=D. E. |last5=Puthoff |first5=H. E. |last6=Terzian |first6=Y. |last7=Tolbert |first7=C. R. |date=1998 |title=Physical Evidence Related to UFO Reports: The Proceedings of a Workshop Held at the Pocantico Conference Center, Tarrytown, New York, September 29 - October 4, 1997 |journal=[[Journal of Scientific Exploration]] |volume=12 |issue=2 |pages=179–229 |location=Stanford, CA |publisher=[[Society for Scientific Exploration]] |issn=0892-3310 |access-date=September 8, 2013 |url=http://www.scientificexploration.org/journal/jse_12_2_sturrock.pdf |display-authors=3 |ref=Sturrock, et al. 1998 |url-status=dead |archive-url=https://web.archive.org/web/20100107163656/http://www.scientificexploration.org/journal/jse_12_2_sturrock.pdf |archive-date=January 7, 2010 }}{{unreliable source?|date=February 2020}} Sturrock panel report on physical evidence.
* {{cite book |last=Sturrock |first=Peter A. |author-link=Peter A. Sturrock |title=The UFO Enigma: A New Review of the Physical Evidence |date=1999 |publisher=Warner Books |location=New York |isbn=0-446-52565-0 |oclc=42645835 |lccn=99066643 |ref=Sturrock 1999 |url=https://archive.org/details/ufoenigma00pete }}
* {{cite book |last=Vallée |first=Jacques |author-link=Jacques Vallée |title=Revelations: Alien Contact and Human Deception |orig-year=Originally published 1991; New York: [[Ballantine Books]] |date=2008 |publisher=[[The Anomalist|Anomalist Books]] |location=San Antonio, TX |isbn=978-1-933665-30-6 |oclc=225866107 |lccn=91091858 |ref=Vallée 2008 |url-access=registration |url=https://archive.org/details/revelationsalien0000vall }}
* {{cite book |last=Viberti |first=Pier Giorgio |title=Incontri ravvicinati: Avvistamenti e contatti da mondi lontani |orig-year=Originally published 1997 |series=Atlanti del sapere |date=2010 |publisher=Giunti Editore |location=Florence |language=it |isbn=978-88-09-75032-6 |oclc=800130536 |ref=Viberti 2010}}

===History===
* {{cite book |last=Clarke |first=David |title=The UFO Files: The Inside Story of Real-Life Sightings |date=2009 |publisher=[[The National Archives (United Kingdom)|The National Archives]] |location=Kew |isbn=978-1-905615-50-6 |oclc=316039535 |ref=Clarke|title-link=The UFO Files: The Inside Story of Real-Life Sightings }} Reports from the UK government files.
* {{cite book | last = Cohen | first = Daniel | title = The Great Airship Mystery: A UFO of the 1890s | publisher = Dodd, Mead & Co. | year = 1981 | isbn = 0396079903 }}
* {{cite book |last=Dolan |first=Richard M. |author-link=Richard M. Dolan |title=UFOs and the National Security State: An Unclassified History, Volume One: 1941–1973 |edition=1st |date=2000 |publisher=Keyhole Publishing Company |location=Rochester, NY |isbn=0-9677995-0-3 |oclc=45546629 |lccn=00691087 |ref=Dolan}} Dolan is a professional historian.
* {{cite book |last1=Downes |first1=Jonathan |last2=Wright |first2=Nigel |title=The Rising of the Moon |edition=Revised |date=2005 |publisher=Xiphos Books |location=Bangor, Northern Ireland |isbn=978-0-9544936-5-3 |oclc=70335856 |ref=Downes & Wright}}
* {{cite book |last1=Fawcett |first1=Lawrence |last2=Greenwood |first2=Barry J. |title=The UFO Cover-up: What the Government Won't Say |others=Foreword by J. Allen Hynek |orig-year=Originally published 1984 as ''Clear Intent''; Englewood Cliffs, NJ: [[Prentice Hall]] |edition=First Fireside |date=1992 |publisher=[[Simon & Schuster]] |location=New York |isbn=0-671-76555-8 |oclc=28384401 |lccn=84009818 |ref=Fawcett & Greenwood 1992}} Many UFO documents.
* {{cite book |last=Good |first=Timothy |others=Foreword by [[Peter Hill-Norton, Baron Hill-Norton|Lord Hill-Norton]] |title=Above Top Secret: The Worldwide UFO Cover-Up |url=https://archive.org/details/abovetopsecretwo00good |url-access=registration |edition=1st Quill |date=1988 |publisher=[[William Morrow and Company]] |location=New York |isbn=0-688-09202-0 |oclc=707516815 |lccn=88208434 |ref=Good 1988 }} Many UFO documents.
* {{cite book |last=Good |first=Timothy |others=Foreword by Lord Hill-Norton |title=Beyond Top Secret: The Worldwide UFO Security Threat |edition=Fully revised and updated |orig-year=Originally published 1996 |date=1997 |publisher=[[Pan Books]] |location=London |isbn=0-330-34928-7 |oclc=38490850 |ref=Good 1997}}
* {{cite book |last=Good |first=Timothy |title=Need to Know: UFOs, the Military, and Intelligence |date=2007 |publisher=[[W. W. Norton & Company|Pegasus Books]] |location=New York |isbn=978-1-933648-38-5 |oclc=180767460 |ref=Good 2007 |url=https://archive.org/details/needtoknow00good }} Update of ''Above Top Secret'' with new cases and documents
* {{cite book |last1=Hall |first1=Michael D. |last2=Connors |first2=Wendy A. |title=Alfred Loedding & the Great Flying Saucer Wave of 1947 |url=http://www.nicap.org/loedding/LoeddingBook.pdf |access-date=September 7, 2013 |date=1998 |publisher=White Rose Press |location=Albuquerque, NM |oclc=41104299 |ref=Hall & Connors |archive-date=March 25, 2018 |archive-url=https://web.archive.org/web/20180325055530/http://www.nicap.org/loedding/LoeddingBook.pdf |url-status=live }}
* {{cite book |last=Keel |first=John |author-link=John Keel |title=Operation Trojan Horse |url=http://galaksija.com/literatura/jk_oth.pdf |orig-year=Originally published 1970 as ''UFOs: Operation Trojan Horse''; New York: [[G. P. Putnam's Sons]] |date=1996 |publisher=IllumiNet Press |location=Lilburn, GA |isbn=978-0-9626534-6-9 |oclc=34474485 |lccn=96014564 |ref=Keel 1996 |url-status=dead |archive-url=https://web.archive.org/web/20130420102608/http://galaksija.com/literatura/jk_oth.pdf |archive-date=April 20, 2013 }}
* {{cite book |last=Kocher |first=George |title=UFOs: What to Do |url=http://www.theblackvault.com/documents/ufoswhattodo.pdf |access-date=September 7, 2013 |date=November 1968 |publisher=[[RAND Corporation]] |id=DRU-1571 |ref=Kocher |archive-date=March 19, 2013 |archive-url=https://web.archive.org/web/20130319134955/http://www.theblackvault.com/documents/ufoswhattodo.pdf |url-status=live }} UFO historical review, case studies, review of hypotheses, recommendations.
* {{cite book |last=Maccabee |first=Bruce |author-link=Bruce Maccabee |title=UFO FBI Connection: The Secret History of the Government's Cover-Up |edition=1st |date=2000 |publisher=[[Llewellyn Worldwide|Llewellyn Publications]] |location=St. Paul, MN |isbn=1-56718-493-6 |oclc=43634902 |lccn=00028277 |ref=Maccabee 2000 |url=https://archive.org/details/ufofbiconnection00phdb }}
* {{cite book |last=Randle |first=Kevin D. |author-link=Kevin D. Randle |title=Project Blue Book Exposed |edition=1st |date=1997 |publisher=[[Da Capo Press|Marlowe & Company]] |location=New York |isbn=1-56924-746-3 |oclc=37047544 |lccn=97072378 |ref=Randle |url=https://archive.org/details/projectbluebooke00rand }}
* {{cite book |last=Ruppelt |first=Edward J. |author-link=Edward J. Ruppelt |title=The Report on Unidentified Flying Objects |url=http://www.nicap.org/rufo/contents.htm |edition=1st |date=1956 |publisher=Doubleday & Company, Inc. |location=Garden City, NY |oclc=1941793 |lccn=56005444 |ref=Ruppelt |access-date=August 28, 2004 |archive-date=May 16, 2011 |archive-url=https://web.archive.org/web/20110516214046/http://www.nicap.org/rufo/contents.htm |url-status=live }} A UFO classic by insider Ruppelt, the first head of the USAF Project Blue Book.
* {{cite book |last1=Swords |first1=Michael |author-link1=Michael D. Swords |last2=Powell |first2=Robert |last3=Svahn |first3=Clas |last4=Olmos |first4=Vicente-Juan |last5=Chalker |first5=Bill |author-link5=Bill Chalker |last6=Greenwood |first6=Barry |last7=Thieme |first7=Richard |last8=Aldrich |first8=Jan |last9=Purcell |first9=Steve |title=UFOs and Government: A Historical Inquiry |date=2012 |publisher=Anomalist Books |location=San Antonio, TX |isbn=978-1-933665-58-0 |oclc=809977863 |display-authors=2 |ref=Swords & Powell |url=https://archive.org/details/UFOsAndGovernment }}
* {{cite book |last=Weinstein |first=Dominique F. |title=Unidentified Aerial Phenomena: Eighty Years of Pilot Sightings |url=http://www.narcap.org/files/narcap_revised_tr-4.pdf |access-date=September 6, 2013 |date=February 2001 |publisher=National Aviation Reporting Center on Anomalous Phenomena (NARCAP) |location=Boulder Creek, CA |id=NARCAP TR-04 |ref=Weinstein 2001 |archive-date=June 12, 2013 |archive-url=https://web.archive.org/web/20130612214228/http://www.narcap.org/files/narcap_revised_tr-4.pdf |url-status=live }}

===Psychology===
* {{cite book |editor-last=Haines |editor-first=Richard F. |title=UFO Phenomena and the Behavioral Scientist |date=1979 |publisher=Scarecrow Press |location=Metuchen, NJ |isbn=0-8108-1228-2 |oclc=5008381 |lccn=79014878 |ref=Haines 1979}}
* {{cite book |last=Jung |first=C G |author-link=Carl Jung |title=Flying Saucers: A Modern Myth of Things Seen in the Skies |others=Translation by R.F.C. Hull |orig-year=Originally published 1958 as ''Ein moderner Mythus: von Dingen, die am Himmel gesehen werden'' |date=1978 |publisher=[[Princeton University Press]] |location=Princeton, NJ |isbn=0-691-01822-7 |oclc=4762238 |lccn=78004325 |ref=Jung |url=https://archive.org/details/flyingsaucersmod00jung }}
* {{cite journal |last=Simón |first=Armando |date=February 1976 |title=UFOs: Testing for the existence of Air Force censorship |journal=Psychology: A Journal of Human Behavior |volume=13 |issue=1 |pages=3–5 |issn=0033-3077 |ref=Simón 1976}}
* {{cite journal |last=Simón |first=Armando |date=1981 |title=A Nonreactive, Quantitative Study of Mass Behavior with Emphasis on the Cinema as Behavior Catalyst |journal=[[Psychological Reports]] |volume=48 |issue=3 |pages=775–785 |publisher=Ammons Scientific |issn=0033-2941 |doi=10.2466/pr0.1981.48.3.775 |s2cid=143670471 |ref=Simón 1981}}
* {{cite journal |last=Simón |first=Armando |date=1984 |title=Psychology and UFOs |journal=[[Skeptical Inquirer]] |volume=8 |pages=355–367 |location=Amherst, NY |publisher=[[Committee for Skeptical Inquiry]] |ref=Simón 1984}}

===Technology===
* {{cite journal |last1=Ford |first1=L. H. |last2=Roman |first2=Thomas A. |date=1996 |title=Quantum field theory constrains traversable wormhole geometries |journal=[[Physical Review|Physical Review D]] |volume=53 |issue=10 |pages=5496–5507 |doi=10.1103/PhysRevD.53.5496 |pmid=10019835 |arxiv=gr-qc/9510071 |bibcode=1996PhRvD..53.5496F |s2cid=18106362 |ref=Ford & Roman}}
* {{cite book |last=Hill |first=Paul R. |author-link=Paul R. Hill |title=Unconventional Flying Objects: A Scientific Analysis |date=1995 |publisher=[[Hampton Roads Publishing Company]] |location=Charlottesville, VA |isbn=1-57174-027-9 |oclc=34075199 |lccn=97109204 |ref=Hill}} Analysis of UFO technology by pioneering NACA/NASA aerospace engineer.
* {{cite journal |last=Krasnikov |first=S. |author-link=Serguei Krasnikov |date=2003 |title=The quantum inequalities do not forbid spacetime shortcuts |journal=Physical Review D |volume=67 |issue=10 |page=104013 |doi=10.1103/PhysRevD.67.104013 |arxiv=gr-qc/0207057 |bibcode=2003PhRvD..67j4013K |s2cid=17498199 |ref=Krasnikov}}
* {{cite web |url=http://www.jumpjet.info/Emergency-Preparedness/Disaster-Mitigation/NBC/Chem/Odors_from_UFOs.pdf |title=Odors from UFOs: Deducing Odorant Chemistry and Causation from Available Data |date=July 2, 2000 |last=Rullán |first=Antonio F. |type=Preliminary paper |access-date=September 13, 2013 |ref=Rullán |archive-date=February 2, 2014 |archive-url=https://web.archive.org/web/20140202033812/http://www.jumpjet.info/Emergency-Preparedness/Disaster-Mitigation/NBC/Chem/Odors_from_UFOs.pdf |url-status=live }}
* {{cite book |last=Sarfatti |first=Jack |author-link=Jack Sarfatti |title=Super Cosmos: Through Struggles to the Stars |date=2006 |publisher=[[AuthorHouse]] |location=Indianapolis, IN |isbn=978-1-4184-7662-5 |oclc=70962499 |lccn=2004095148 |ref=Sarfatti}}

===Skepticism===
* {{cite book |last=Plait |first=Philip C. |author-link=Phil Plait |others=Illustrations by Tina Cash Walsh |title=Bad Astronomy: Misconceptions and Misuses Revealed, from Astrology to the Moon Landing "Hoax" |date=2002 |publisher=[[John Wiley & Sons|John Wiley & Sons, Inc.]] |location=New York |isbn=0-471-40976-6 |oclc=48885221 |lccn=2002277382 |chapter=Misidentified Flying Objects: UFOs and Illusions of the Mind and Eye |ref=Plait|title-link=Bad Astronomy }}
* {{cite web |url=http://www.ianridpath.com/ufo/astroufo1.htm |title=Astronomical Causes of UFOs |last=Ridpath |first=Ian |author-link=Ian Ridpath |publisher=Ian Ridpath |access-date=July 13, 2013 |archive-date=May 16, 2013 |archive-url=https://web.archive.org/web/20130516202705/http://www.ianridpath.com/ufo/astroufo1.htm |url-status=live }}
* {{cite book |last=Seeds |first=Michael |title=Horizons: Exploring the Universe |edition=2nd |orig-year=Originally published 1981 |date=1995 |publisher=[[Cengage Learning|Wadsworth Publishing]] |location=Belmont, CA |isbn=0-534-24889-6 |oclc=30156735 |lccn=94013521 |ref=Seeds}}(Appendix A)
* {{cite book |last=Sheaffer |first=Robert |title=Psychic Vibrations: Skeptical Giggles from the Skeptical Inquirer |url=https://www.createspace.com/3630764 |access-date=July 13, 2013 |edition=2nd |orig-year=Originally published 2011 |date=2012 |publisher=[[Amazon.com#Acquisitions|CreateSpace]]<!--No correction needed.--> |location=Charleston, SC |isbn=978-1-4636-0157-7 |ref=Sheaffer 2011 |archive-date=January 16, 2013 |archive-url=https://web.archive.org/web/20130116020703/https://www.createspace.com/3630764 |url-status=dead }}
{{refend}}

==External links==

{{Sister project links|UFO|voy=UFOs}}
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* [https://web.archive.org/web/20090204125620/http://ucblibraries.colorado.edu/govpubs/us/ufos.htm "Government Reports on UFOs"] from the Government Information Library at the [[University of Colorado Boulder]]
* [https://www.cia.gov/static/105bd8290b90de13ee136fecc9fe863f/cia-role-study-UFOs.pdf "CIA's Role in the Study of UFOs, 1947–90"] {{Webarchive|url=https://web.archive.org/web/20191001174318/https://www.cia.gov/library/center-for-the-study-of-intelligence/csi-publications/csi-studies/studies/97unclass/ufo.html |date=October 1, 2019 }} by Gerald K. Haines, [[Central Intelligence Agency]]
* [https://web.archive.org/web/20160729151447/https://www.cia.gov/library/readingroom/collection/ufos-fact-or-fiction "UFOs: Fact or Fiction?"] Declassified CIA documents from the 1940s through the early 1990s.
* [https://www.gov.uk/government/publications/ufo-reports-in-the-uk "UFO Reports in the UK"] from 1997 to 2009 by the [[Ministry of Defence (United Kingdom)|Ministry of Defence]]
* [http://www.nationalarchives.gov.uk/ufos/ "Newly released UFO files from the UK government"] at [[The National Archives (United Kingdom)|The National Archives]]
* [https://web.archive.org/web/20160116131034/http://www.collectionscanada.gc.ca/ufo/ "Canada's UFOs: The Search for the Unknown"], a virtual museum exhibition by the [[Library and Archives Canada]]
* [http://that1archive.neocities.org/subfolder1/ufo-files.html Declassified files on UFOs from many countries]
* [http://www.huffingtonpost.com/entry/groundbreaking-ufo-video-just-released-from-chilean_us_586d37bce4b014e7c72ee56b Declassified video – Chilean UAP event of November 11, 2014] ([http://www.cefaa.gob.cl/home/en-la-prensa/noticias/casoarmada official]; [https://www.youtube.com/watch?v=NkUTGpegZN0 video (9:59)])
* [https://www.nytimes.com/2021/05/30/opinion/ufo-sightings-report.html An astrophysicist's view of UFOs] ([[Adam Frank]]; [[NYT]]; May 30, 2021)
* [http://www.fraknoi.com/wp-content/uploads/2021/05/Responding-to-Claims-about-Alien-UFOs-2.pdf A list of skeptical resources] (astronomer [[Andrew Fraknoi]])
* [https://www.youtube.com/channel/UCF3UCTZiVg9wrIEzO7Om6jw UFO Explanations] (videos; scientist [[Mick West]])
* [https://www.wsj.com/amp/articles/ufos-uaptf-unidentified-aerial-phenomena-lipf-national-security-11627582598 Some UAPs may be laser-generated holograms?] ([[WSJ]]; July 29, 2021).
* [https://www.scientificamerican.com/article/to-understand-uap-we-need-megapixel-imagery/ UAPs need a high-resolution image] ([[Avi Loeb]]; [[Scientific American]]; August 2, 2021).
* {{youTube|aSDweUbGBow|Video (92:50): U.S. Congressional Hearing on UFO/UAP (May 17, 2022)}}.

{{UFOs}}
{{Extraterrestrial life}}
{{Conspiracy theories}}
{{Authority control}}
{{Portal bar|Physics|Speculative fiction|Aviation|Weather|}}

[[Category:Unidentified flying objects| ]]
[[Category:Alleged extraterrestrial visitation]]
[[Category:Atmospheric optical phenomena]]
[[Category:Legendary flying machines]]
[[Category:Phantom vehicles]]
[[Category:Supernatural urban legends]]
[[Category:Unexplained phenomena]]

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