I I actually haven't witnessed it in a while, but isn't there the implementation for AI to do just that - take off and defend an airfield under attack? Was that in an earlier version?
I also remember some fun scenario missions from OldHat that I had but lost in one of the reinstalls a while back. O =ne of the missions was an attack on Rumbeke airbase, with the Germans defending. Alas, I can't find an active download link for them; anyone else remember them? They're noted here, but the link is dead... link