This sophisticated multiplayer WWII combat flight simulator uses declassified WWII flight test data. It incorporates true six-degrees-of-freedom and force-based flight modeling, which gives the aircraft a realistic feel. You can fly in aerial combat missions against other players from all over the world. Battle a "real" Japanese squadron of A6M Zeros, or tangle with a British ace in a Spitfire.
This is the full installation of the program with all 50 planes and cockpits.