Final scenes shot on location at Los Angeles Metropolitan Airport (Van Nuys Airport). These scenes taken on Waterman Drive which is same location as used in Casablanca (1942).
There has been open speculation that the plot of this film, in part, later inspired President Ronald Reagan to undertake the Strategic Defense Initiative, better known as Star Wars.
Much stock footage used including shots of Union Air Terminal (Burbank Airport), USN airship operations, and footage taken from Ceiling Zero (1936) and Secret Service of the Air (1939).
The Rice Commission in this film is modelled after the actual "Dies Sessions", a congressional committee at the time investigating espionage and sabotage in the United States.
The character "Tom Saxby" in the previous 3 films of the series signs his name as "William Saxby" in a telegram to Bancroft.