In game there are guys who specialize in the 51 who can shoot down (aka defeat) just about anything most of the time. Same can be said for everyone else in game who specializes in a single aircraft type be it 109s, Yaks, Zekes, 38s....
If this game and the historical record ever come together it is on this point: The guy flying the plane (or as it would be in the case of AH, playing) tends to be the deciding factor most of the time.
Luck comes into the equation pretty much as it always does.