WWII Online is basically a flight sim that just happens to have the army and navy along with a 1/2 scale map of western europe along with it. If you're into realism, and would like the option of not only flying, but driving tanks.. etc... it might be for you. The game has a steep learning curve, but once you get the basics, you can compete with anyone... at least on the ground.
Flying is a different story. You need to know tactics.
Only downside is its 15 bucks a month.