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.
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.
The Warner Brothers' Ranch near Los Angeles also became the airfield set for the film's opening sequence at the American Volunteer Group (AVG) base Kunming. There a trio of the full-scale P-40 mock-ups built several years earlier for Flying Tigers (1942), were evident in the background, along with two P-40Es reclaimed from the AAF Reclamation Depot in San Diego.
Despite objections to an early screenplay, expressed in a September 30, 1943 memo from Colonel William Westlake, assistant to the Director for Army Air Forces, to Allyn Butterfield, Chief of the Feature Film Section of the War Department Bureau of Public Relations, a revised screenplay met with Air Force approval, and by October 1943, War Department cooperation was granted.