Following the dramatization of Mantell's plane crash, both the script and movie remain mostly faithful to one another as the story of the Air Force's "Project Sign" implementation is narrated. The major difference comes about when a brief interview with American Airlines pilot Capt. Willis T. Sperry appears in the film. The script itself carries no mention of Sperry whatsoever at this point, so we may assume that negotiations for Sperry's participation were finalized closer to the time of actual production.
Though Sperry later claimed there were no problems in getting permission from American Airlines to recount his UFO encounter on camera, one wonders if, at least, second thoughts made the corporate rounds when word that a commercial pilot was actually going to "tell all" about a highly intriguing UFO event became obvious. From the way Sperry posed in full pilot attire near a runway with an aircraft as a backdrop, we might almost think that American Airlines looked forward to publicity on the big screen -- and surely that would be an anomaly, considering the tight-lipped manner in which the major airlines generally reacted to UFO encounters in the fifties (particularly when close approaches resulting in evasive action and passenger panic or injuries occurred), fearful that "saucers" could scare away the flying public.
Nevertheless, acquiring Sperry for a segment in "U.F.O." was a definite bonus and helped tremendously to infuse the authenticity necessary for a documentary approach. Unlike the labored Mantell scenes, Captain Sperry's story was laid out in about 90 seconds, and this segment, filmed in an airport environment, must have looked spectacular to the curious on a 1956 theater screen.
The scenes move swiftly at this point, and as quickly as the audience is told of Project Sign's origin, a narrator states the agency was soon terminated. Of some interest, in the movie we are told, "On January 9, 1950, the press reported that Project Sign was closed. From now on, the Air Force stated, its only similar activity would be the routine, conventional watch for unidentified flying objects."
However, the script varies here, informing us in these words: "On January 9, 1950, the press reported that the Air Force announced that Project Sign, including pictures of flying saucers, none of them genuine, will be placed on public exhibition in the Pentagon."