 With over 30 aircraft in the air, the flying scenes were complex to shoot, and can be compared to the 1969 film "Battle of Britain" where large formations of period-specific aircraft were filmed in staged aerial battles.The 2001 film "Pearl Harbor" would use some of the same modified aircraft.Parts of the film showing the takeoff of the Japanese aircraft utilize an , "Yorktown", which was commissioned in 1943 and modernized after the war to have a very slightly angled flight deck.