What's an "arcade"?
If by "arcade" you mean "an amusement center having coin-operated games" (Merriam-Webster) it is most definitely a place of amusement with a $15 Credit Card Fee taking the place of coins.
I suspect that you use "arcade" in a derogatory manner, as if amusing yourself online with simulated WW2 aircraft in simulated combat is some sort of embarassing or less-than-worthy hobby.
In any event, I am not aware of any PC-based, massively-multiplayer Internet programs built around flying that come anywhere close to qualifying as a "flight simulator" in the true sense of those words.
So, like all the other MMOG Air Combat sims, AH is a game. And a GREAT GAME at that.