Second unit director John Jordan refused to wear a harness during a bomber scene. While giving a hand signal to another airplane from the tail gunner position in the camera plane, he lost his grip and fell 4,000 feet to his death.
Director Mike Nichols wanted thirty-six B-25s to create the big U.S. Army Air Forces base, but the budget couldn't stretch to more than seventeen flyable Mitchells. An additional non-flyable hull was acquired in Mexico, made barely ferry-able and flown with landing gear down to location, only to be burned and destroyed in the landing crash scene. The wreck was then buried in the ground next to the runway, where it remains to this day.
The production crew all wore military uniforms during filming so, if they wandered accidentally into shot, they wouldn't affect the filming.
While on a tirade in his office, Major Major (Bob Newhart) walks past a framed photo of Franklin D. Roosevelt. In a continuous shot, he paces around his office, and when he passes the picture again, it is of Winston Churchill, as he makes one more round of his office and grabs the fake mustache out of his filing cabinet, the photo has changed to that of Joseph Stalin.
George C. Scott turned down the role of Colonel Cathcart, saying he had effectively played the same part in Dr. Folamour ou : comment j'ai appris à ne plus m'en faire et à aimer la bombe (1964).