Author Craig Thomas' 1983 sequel to "Firefox", the novel "Firefox Down", is dedicated to Clint Eastwood. The dedication reads: "For Clint Eastwood - pilot of the Firefox".
The footage of the "Mother One" submarine breaking the surface ice was recycled from Ice Station Zebra (1968).
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.
In this movie, General Vladimirov (Klaus Löwitsch) assures the First Secretary (Stefan Schnabel), "No pilot will risk the Moscow defenses, however invisible he might be." On May 28, 1987, a young German pilot flew his small plane five hundred miles into Soviet airspace and landed safely in Red Square. He was promptly arrested.
Fritz Manes: Clint Eastwood's regular producing partner as a Captain. The appearance was one of seven that Manes has made in Eastwood's movies.