Additional background photography was shot at RAF Barford St John, a satellite station of RAF Croughton in Oxfordshire, England. Officially the airfield is still under Ministry of Defence ownership following its closure in the late 1990s as a Communications Station linked to the since closed RAF Upper Heyford. Other locations around Eglin AFB and Fort Walton also served as secondary locations for filming. The crew used 12 B-17s for filming which were pulled from QB-17 drones used at Eglin and other B-17s from depot locations in Alabama and New Mexico. Since some of the aircraft had been used in the 1946 Bikini atomic experiments and absorbed high levels of radioactivity, they could only be used for shooting for limited periods.