the way i see it, its like this. the object is to capture the other guys' base. in the case of an air base, you want to take out the town, but the other guy is on the defensive and ups every thing he can to defend the town and the base. the only way to gain air superiority is to kill fighter hanger, bomber hangers ords, ack etc. there is nothing sacred about taking the other guys property.
I've also re-thought the whole vulching thing. if you're trying to take the town and you have 2 guys cover the air base, vulching is going to happen. you'd be crazy not to. therefore this is my thought. Vulching is fair game if the guy is taking off or landing. i would say, if he's got his wheels down and is landing, give him a break cause there are no extra points for killing the guy. The civil thing to do is let him land. On take off and you're trying to take a base, all bets are off!