Note that the 'secret' base was in the Ukraine. One of the key planners was the unheralded Col. (later Gen.) Ben Kelsey, who's seen in some of the movie shots.
He's best known for his XP-38 record flight coast to coast, but also was Jimmy Doolittle's safety pilot in the world's first blind flight. Kelsey was the planner and spark plug behind the Allison V-12 V1710, and the P-39, P-38, and P-51. Against doctrine, he pushed for droppable fuel tanks for fighters, so that capability was engineered into them before WWII. His impetus resulted USAAC aircraft getting specified for self sealing fuel tanks and bullet resistant windscreens. He also planned and led the first trans Atlantic ferrying of fighters. EVERYONE should read his Dragon's Teeth book which advocates always being prepared for war in peacetime, citing our experience in WWII.