When I watch these American WW2 propaganda films ... I am always looking for inaccuracies. The biggest one I can find in this film is the the AVG (Flying Tigers) did not engage the Japanese until after Pearl Harbor (12-12-41). That's pretty significant.
Please feel free to add more if you know them.
It's in the "goofs" section. Most every source I've seen says they first saw combat in the air against the Japanese over Kumming on December 20th, 1941, not the twelfth. Though, they had attacked ground targets before that.
The historic mistakes are much more common in movies from following decades, as opposed to when the war was still in progress.