Well don't have a "favorite" because situations vary in AH2 so much that you really need to have at least 2 fighters unless your an ace.
Mine are the La-7 for furballing. Lol everyone attacks me, but half are TERRIBLE turners. Omg, once I got into a turning fight with a Fw190A8.
The P-51D for sucker punching someone.
P-47N for multi role. I think it is one of if not THE most flexible planes in the game.
C205 because everyone I fight thinks it will be an easy kill, but sadly I've only gotten assists so far.
and Fw190D because I love it.