I fought Bish earlier today. Id up a flak and kill a guy, then an IL 2 and kill some gvs. They'd move to another base, where there was no defense, rinse repeat. It depends on the players. Some guys like a good knock down dragout, others want the easy win. I hate the "Shop for an easy target" game. It takes all the feel of combat out, and turns the game into Mother May I.
Once an attack is started, it should follow through till one side gives in due to better flying of one side, or numbers log off.