Errol Flynn was criticized for playing heroes in WWII movies. Tony Thomas in his book 'Errol Flynn: The Spy Who Never Was' states that Flynn had tried to enlist in every branch of any armed services he could but was rejected as unfit for service on the grounds of his health. Flynn had a heart condition, tuberculosis, malaria and a back problem. Flynn felt he could contribute to America's war effort by appearing in such films as this one, Edge of Darkness (1943), Northern Pursuit (1943), Objective, Burma! (1945), and Uncertain Glory (1944). Reportedly, Flynn was at his most professional and cooperative he ever was while working on WWII-themed movies. The studios apparently did not diffuse the criticism of Flynn's state of health as they wished to keep it quiet for fear of his box-office draw waning. Flynn's real-life medical condition adds more bite to the line MacMurray's character says to him after the death of a squadron mate: "Are you an example of sound medical basis?".
It was of interest that Lt. Douglas Lee's log book lists his first flying lesson as 12/7 (1941), an incredibly prophetic selection of a date. That of course was the same day as the "day of infamy" when Japanese planes descended with such ferocity on the U.S. fleet in Pearl Harbor. The movie had been released months prior to that, in August 1941.
One of the pilots who flew the planes in the film footage was Navy Lt. Edward "Butch" O'Hare. He served as a fighter pilot in the Pacific and shot down five Japanese planes in his first battle, earning ace status and the Medal of Honor. He would go on to down 12 planes total and become one of the top heroes of the war before he was killed in action off the Gilbert Islands in November, 1943. O'Hare International Airport in Chicago was later named for him.
The first feature film to contain sequences photographed on 35mm color negative film, in this case Technicolor Monopack used for the aerial sequences. Previous color features used black and white negative film photographed behind color filters. Technicolor Monopack could be used in a standard 35mm camera instead of the bulky 3-strip Technicolor cameras.
Paul Mantz, who performed many of the aerial sequences in this film, was later killed while performing one of the aerial sequences on The Flight of the Phoenix (1965).