Deliberate mistake: In one of the dogfight scenes a Japanese Zero crashes into a tower. It's a quick shot, but you can still see that what crashes is an American P-40 with Japanese markings.
Deliberate mistake: It's 1941 in a military base and no one is smoking...
Answer: From Dec 7, 1941 to Sept 22, 1943, the Purple Heart was also awarded for meritorious performance of duty. For wounds, "in combat" is much more restrictive than the actual requirements. Any injury caused directly or indirectly by a hostile foreign agency counts, including friendly fire if it was intended to hit an enemy.
Myridon