Radar played an essential role in the movie, especially when coupled with a pilot's visual observation of multiple UFOs during the story's climax. In keeping with the documentary flavor of "U.F.O." the producers apparently wanted to blend reality with dramatic scenes, from the publicity aspect. Lobby card no. 3 shows (from left) producer Clarence Greene, radar expert Wendell Swanson (seated, who played himself in the film) and former Air Force captain and Project Blue Book chief Edward J. Ruppelt at a radar unit. Ruppelt and Swanson, along with Maj. Dewey J.Fournet, Jr. and Albert M. Chop, worked with the production staff to assure accuracy. Greene, per the blurb on most of the posters, lobby cards and other material, truly enlisted "the people who lived the story of the UFO" to construct his project. As time goes on, all -- all of these men -- will become legend. For their stories, yes, but infinitely more because of their integrity, and honorable people will take notice.