The original plan was to use a Swedish JA 37 Viggen jet fighter as the Soviet aircraft, but the Swedish government refused permission.
Because his role in the movie required him to speak some Russian, Clint Eastwood prepared by studying the language with resources provided by the U.S. Military's Defense Language Institute.
The story was loosely based on an actual event in which a Soviet fighter pilot (Viktor Belenko) defected to Japan on September 6, 1976. Belenko was stationed in Chuguyekva, Primorsky Krai, R.S.F.S.R. (Soviet Russia) where he flew a MiG-25 to Hakodate, Japan. During his defection, he brought the pilot's manual, where the U.S. Air Force were, and American personnel evaluated and tested the aircraft. The U.S. Air Force determined that the MiG-25 was more of an interceptor rather than a fighter-bomber (which the F-15 Eagle had a superior edge, later demonstrated by the Israeli Air Force where it was used in combat against Syrian MiGs (they also operated the MiG-25 with no losses). {This may or may not be significant, the MiG-25 flown by the Syrians would have been the "export" model, the versions of military aircraft most major nations sell are of lower performance than the home models.} The captured MiG was later dismantled by the Japanese technicians and returned to the Soviet Union.