I got this game just recently and I've already played through the campaign on realistic. Single player is pretty fun, but on the other hand I haven't found a single game online that isn't arcade.
In my opinion realistic difficulty isn't too hard to start out with. Just remember to turn down the sensitivity in options if you stall all the time - shouldn't be necessary for some planes though.
I used the training mode to fool around, and get the feel of different planes. Just pick a bomber as your enemy and set the AI to Rookie... He won't be able to shoot you down in a million years, so you're free to roam around. Helps alot!
