Why is the P-51 mustang not in blazing angels 2

I'm not sure. I love the game, but the game doesn't seem complete without such a classic American plane, right? Most of the planes in the game are British, but the game is centered around an American squadron. It doesn't really make sense, but since they wasted a lot of time making enemy aircraft (a real American pilot wouldn't get caught dead in an enemy plane), they probably couldn't fit it in there (you know what I mean?). Hope this helps.