[13] By December 1949, author Donald Keyhoe promoted the idea that the Air Force was withholding knowledge of interplanetary spaceships, culminating in his 1955 work The Flying Saucer Conspiracy.

[3]: 44  By 1974, theories alleged the Air Force stored dead alien bodies at a mythical "Hangar 18", and in 1980, the book The Roswell Incident introduced the story of a UFO crash to a mass audience.

[3]: 6 [14] While earlier decades imagined a coverup of benevolent "space brothers", the 1980s saw the rise of what scholars called "ufology's dark side": theories that a government cabal was secretly involved with a race of malevolent aliens.

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 small but vocal groups of ufologists who favour unconventional or pseudoscientific hypotheses, often claiming that UFOs are evidence of extraterrestrial intelligence, technologically advanced cryptids, demons, interdimensional contact or future time travelers.

[1]: 258  Several proponents later confessed responsibility for hoaxes or lies, including Gray Barker, Carl Allen, Richard Doty, Bill Moore, and Ray Santelli.

[20][12]: 225 21st century proponents include former Canadian Defence Minister Paul Hellyer, Stanford University immunologist Garry Nolan,[21] and Israeli brigadier general Haim Eshed (former director of space programs for the Israel Ministry of Defense),[22] In 2017, To The Stars Inc. was founded by Jim Semivan, Harold E. Puthoff, and Tom DeLonge.

In March 2001, former astronaut and United States Senator John Glenn appeared on an episode of the TV series Frasier playing a fictional version of himself who confesses to a UFO coverup.

[1]: 323 [10] Beginning in 1945, Palmer began to print ostensibly-true stories based on the writings of Richard Shaver, a Pennsylvania welder who claimed to be in telepathic communication with a secret underground race.

[1]: 13–15 In the October 1947 issue of Amazing Stories, editor Raymond Palmer argued the flying disc flap was proof of Richard Sharpe Shaver's claims.

"[4][9]: 159 [note 2] During the last decades of his life, Shaver devoted himself to "rock books"—stones that he believed had been created by the advanced ancient races and embedded with legible pictures and texts.

In 1955, Donald Keyhoe authored a new book that pointedly accused elements of the United States government of engaging in a conspiracy to cover up knowledge of flying saucers.

[1]: 47–48 [46] In 1952 and 1956, True magazine published articles by San Francisco Chronicle reporter John Philip Cahn[47][48] that exposed Newton and "Dr. Gee" (identified as Leo A. GeBauer) as oil con artists who had hoaxed Scully.

[6]: 106 In 1957, Jessup was invited to the Office of Naval Research where he was shown an annotated copy of his book that was filled with handwritten notes in its margins, written with three different shades of blue ink, appearing to detail a debate among three individuals.

[3]: 30–31 In the novel and film 2001: A Space Odyssey by Arthur C. Clarke and Stanley Kubrick, American discovery of an extraterrestrial artifact prompts a cover up and disinformation campaign with fatal consequence for astronauts sent to investigate.[5]: ch.

[68] In 1976, pulp publisher Ray Palmer argued "there is a definite link between flying saucers, The Shaver Mystery, The Kennedy’s assassinations, Watergate and Fred Crisman.

[72] In 1974, science-fiction author and conspiracy theorist Robert Spencer Carr alleged that alien bodies recovered from the Aztec crash were stored in "Hangar 18" at Wright-Patterson.

[12]: 331 Decades later, Carr's son recalled that he had often "mortified my mother and me by spinning preposterous stories in front of strangers... [tales of] befriending a giant alligator in the Florida swamps, and sharing complex philosophical ideas with porpoises in the Gulf of Mexico.

[1]: 227 [80] Science writers Philip J. Klass and Michael Shermer highlight a potential motive for the hoax was to provide an "Act of God" that would allow the crew to avoid a steep financial penalty from the Forestry Service for failing to complete their contract by the deadline.

[1]: 235–238  Also in 1987, established horror author Whitley Strieber released Communion, an ostensibly non-fiction autobiographical ab duction tale; It topped the New York Times bestseller list.

[2]: 69–70  Law enforcement recovered radar chaff, syringes, and a gas mask; Some of the corpses had rope marks and broken bones, as if they had been hoisted onto a helicopter and dropped onto he ground.

[2]: 85  In 1979, the idea of aliens causing "mutiliations" was ridiculed when it was reported that a mutilated bull had been drugged with Thorazine; Law enforcement told press: "We know this stuff is made here, and it isn't from outer space.

[4]: 87–88  Bennewitz was befriended by Richard Doty, an Air Force Sergeant, who fed him false stories of a UFO conspiracy, government treaties with extraterrestrials, and alien harvesting of cattle.

[5]: ch 7  On August 25, 1988, Lear authored a post titled "The UFO Coverup" which incorporated elements of mythos from Paul Bennewitz, a ufologist who was later revealed to have been fed disinformation by American counter-intelligence agent Richard C.

[111] In 2018, columnist Colin Dickey noted Lear and Cooper's influence, writing "in the early years [UFO writers] did not, by and large, embrace strong political positions.

[111] In 1991, Cooper published the influential conspiracy work Behold a Pale Horse which claimed that Kennedy was killed after he "informed Majestic 12 that he intended to reveal the presence of aliens to the American people".

Barkun observes that the show's oft-repeated mantra "Trust No One" serves to "neatly encapsulate the conspiracist's limitless suspicions",[2]: 2  while Gulyas describes the series as "an exemplar of paranoid television, embracing the mounting paranoia and tensions of the 1990s".

[3]: xii The X-Files incorporated elements of UFO conspiracy theories, including a shadowy cabal of conspirators, a Roswell coverup, Men in Black, and a 'treaty' allowing alien abduction.

The show provided an alternative history that "wove nearly every significant historical event of the past fifty years into a paranoid vision of extraterrestrial infiltration."[3]: ch.

Arizona Governor Fife Symington III held a press conference, joking that "they found who was responsible" and revealing an aide dressed in an alien costume.

[32][154] Grusch "became a hot new topic in the UFO world" and his claims "ignited a new wave of interest in extraterrestrial life",[155] but his story was criticized for its lack of verifiable evidence.