During pre-production, Joseph W. G. Clark, the public relations director of the British Commonwealth Air Training Plan was heavily involved in promoting a film project that was initially identified as "Bush Pilots" based on a script submitted by Canadian screenwriters. With RCAF backing, Hal Wallis and Jack Warner were approached in Hollywood to undertake a "patriotic film." Warner was enthusiastic, and began the task of casting a major star to front the project. After considering Raymond Massey, Errol Flynn, and Clark Gable, the decision was made to cast George Brent, but Warner Bros. was unsure whether he could carry the film. Numerous attempts to rewrite the script into a more acceptable form resulted in a final screenplay now titled "Captains of the Clouds". The name was borrowed from a Victory Loans speech given by Billy Bishop. The only holdup was casting, which was resolved when Warner persuaded its resident "cocky guy" (as producer Jerry Wald had dubbed him), 42-year-old James Cagney, to take on the lead male role.