Trivia: Even though the US military had a big part in the production of this film they asked the producer (John Wayne) not to credit them because they thought the movie was so pro-military that it bordered on propaganda.
Trivia: The idea of helicopters was not necessarily new in WW2, but effective designs were not made until after the war; there is evidence from some literary sources (one of them being a book named "German Secret Weapons of WW2" or something like that) that the Germans did indeed conduct experiments and designs on this vehicle type.