While the dogfights were shot in Ireland over a two-week period using actual vintage planes, the crash sequences were filmed at Andrews Air Force base in a single day, using models assembled by a group of teenaged hobbyists Roger Corman happened across while scouting locations.
Production was shut down briefly due to a disaster on another semi-related film in the area. Birch Williams, an American living expat in Ireland, was the owner of the period planes Roger Corman leased for the production. He was so interested in and excited by what Corman was doing that he decided to make a similar film himself, using his own planes. Unfortunately, there was a midair mishap, and Williams and two pilots were killed. In response, the Irish government shut down all film flying, and the insurance company canceled Corman's policy. It took several days of negotiation to get their status restored, and to resume production.
Stunt pilot Charles Boddington was killed during filming when the vintage biplane he was flying crashed at Weston aerodrome near Dublin. The following day, another aircraft crashed, injuring pilot Lynn Garrison and actor Don Stroud.