AH has the ULTIMATE upperhand in providing various situations, due to its MMOG nature. IL2/FB is also capable of large multi-player sessions and yet, frankly, it's still not much more than just a loosely-fit furball. AH also holds better FM and user-friendliness.
However, IL2/FB has some pretty neat attention to details, which can make a lot of difference when both games feature same vintage WW2 prop-aircraft. Also, it's graphically superior no doubt.