A large number of film models were assembled for the production; for the more than 80 aircraft appearing in the film, static mock-ups and models were used as well as authentic aircraft of the period. Lieutenant Colonel Duncan Wilmore, USAF (Ret) acted as the United States Air Force liaison to the production, beginning his role as a technical consultant in 1980 when the pre-production planning had begun. The first draft of the script in 1980 had concentrated only on the Mercury 7 but as subsequent revisions developed the treatment into more of the original story that Wolfe had envisioned, the aircraft of the late-1940s that would have been seen at Edwards AFB were required. Wilmore gathered World War II era "prop" aircraft including: