Actually, IMHO it would be kinda cool if damage to your aircraft were to have an affect - although exactly what in the context of AH would make sense I'm unsure. Something to simulate the amount of work the ground crew would need to do to return the airframe to service, at any rate.
And on a related thought, as much as I detested the lack of visibility (2 1/2 miles and "pea soup") and performance issues in WWIIOL, the implementation of supply made for tremendous richness to the sim itself - and on the airwar front, it greatly increased desire to successfully return your aircraft to an airfield, which had a positive effect on how many people flew because if you lost your ride you might not be able to get another. And for the war effort, it meant that attrition had an affect - shooting someone down meant something more than just removing an immediate threat for the next 3 minutes.
Of course the flip-side is that it made for significant opportunities for player-player clashes, too. Idiots who took off under a cap affected your ability to take an aircraft later when the field wasn't capped, and it was highly frustrating to sign onto the game and find no aircraft to fly anywhere. And accusations of griefing were the order of the day. Especially while many took into account the supply limitations and flew accordingly, many did not - so it really highlighted in a negative way the individualistic nature of a MMOG and the lack of top-down control that are the extreme opposite of a real military venture.
But when it worked right, it was pretty awesome.
