The book was a success, and led to a freelance writing career, with Keyhoe's articles and fictional stories (mostly related to aviation) appearing in a variety of publications.

[citation needed] Keyhoe returned to active duty during World War II in a Naval Aviation Training Division before retiring again at the rank of major.

[9] Keyhoe wrote a number of air adventure stories for Flying Aces, and other magazines, and created two larger-than-life superheroes in this genre.

[10] Keyhoe's other "superpowered" flying ace was Richard Knight, a World War I veteran who was blinded in combat but gained a supernatural ability to see in the dark.

[12] Many of Keyhoe's stories for the pulps were science fiction or Weird Fantasy, or contained a significant measure of these elements — a fact that was not lost on later critics of his UFO books.

For some time, True (a popular American men's magazine) had been inquiring of officials as to the flying saucer question, with little to show for their efforts.

In the spring of 1949, after the U.S. Air Force had released contradictory information about the saucers, editor Ken Purdy turned to Keyhoe, who had written for the magazine, but who also had friends and contacts in the military and the Pentagon.

[citation needed] As their forms, flight maneuvers, speeds and light technology was apparently far ahead of any nation's developments, Keyhoe became convinced that they must be the products of unearthly intelligences, and that the U.S. government was trying to suppress the whole truth about the subject.

"[17] Capitalizing on the interest, Keyhoe expanded the article into a book, The Flying Saucers Are Real (1950); it sold over half a million copies in paperback.

[citation needed] Carl Jung argued that Keyhoe's first two books were "based on official material and studiously avoid the wild speculations, naivete or prejudice of other [UFO] publications.

[21] Historian of folklore Curtis Peebles argues: "The Flying Saucer Conspiracy marked a shift in Keyhoe's belief system.

He was one of several prominent professional, military or scientific figures on the board of directors, which lent the group a degree of legitimacy many of the other contemporary "flying saucer clubs" sorely lacked.

[24] NICAP founder Thomas Townsend Brown was ousted as director in early 1957 after facing repeated charges of financial ineptitude.

They scored some attention from the mass media, and the general public (NICAP's membership peaked at about 15,000 during the early and mid-1960s) but only very limited interest from government officials.

[citation needed] On January 22, 1958, Keyhoe appeared on a CBS live television show the Armstrong Circle Theatre to speak on the topic of UFOs.

[26] On March 8, 1958, Keyhoe appeared on The Mike Wallace Interview on ABC and spoke about flying saucers, contactees and the details of the Armstrong Circle Theatre censorship, which he blamed on the Air Force rather than CBS.

In the episode, "The Lubbock Lights" (aired January 22, 2019), Keyhoe is a writer (spelled in the IMDB credits as "Donald Kehoe") who federal agents try to intimidate into clearing his UFO stories through them before publication.

[29] Additionally, The UFO Investigator, the organization's newsletter, which was edited and published by Keyhoe, gradually moved from being delivered on a reliable monthly basis in the mid-1960s to an increasingly erratic and unreliable delivery schedule, which angered many NICAP subscribers.

It promoted "Operation Lure", a plan to entice extraterrestrials to land on Earth, and described the problems Keyhoe had getting information from government agents.