Richard Loo who plays the notorious "Tokyo Joe" in this film was also in Flying Tigers (1942) as Dr. Tsing who was staff physician for the AVG (American Volunteer Group).
In order to provide authentic aerial sequences, the principal photography took place in July-August of 1944 at Luke Auxiliary One airfield in Arizona. The use of Training Command Curtiss P-40Es and Fs, some one dozen North American B-25Gs and various other training aircraft helped create a busy sky, but unfortunately also led to the loss of five airmen in a midair collision.
This was at one time to be a Hal B. Wallis production. According to memos included in the records of the War Department, Wallis wanted Colonel Robert L. Scott to play himself in the film, and if that were not possible, wanted Scott to contribute to the script, as he believed the pilot's contribution would make the screenplay more effective. The Army Air Force denied this request, as they believed it would interfere with Scott's military duties. By February 1, 1944, however, Scott was made available for temporary duty as a technical advisor.
According to a March 22, 1945 letter from Brig. Gen. Ray L. Owens to Pain, Lowe & Coffin, Esqs. contained in the holdings at NARS, Lieut. Patrick D. Holland was killed during aerial manoeuvres that comprised part of his military training and the flight was photographed by the film's cameramen and included in the picture.