I would add that the movie, while excellent, took many liberties as movies do, but the book of the same title (written, IIRC, by a prisoner who was there) was excellent. And the proper term is "murdered", not "executed", since the POWS at that point were considered noncombatants and had committed no crime.

To bring it back to airplanes, the fun scene where James Garner steals a German plane and attempts to fly it back to England is fictional. One of the escaped prisoners did try the same thing but never got off the ground; he was caught by a guard while trying to get the plane started.