You could always play with house rules. I personally like allowing two to fire per territory. Makes AA carry a bit more weight.
this would be TOOO powerful…. in the rules a single AA Gun in a territory fires ONCE at EACH fighter, Then ONCE at EACH Bomber.
so if (some Land Units) 5 fighter and 2 bombers enter a territ …
and the bombers are doing a raid while the fighters (and other land units) are in combat.
that means the AA Gun 1st gets 5 shots at fighters, then 2 Shots at bombers… any ONE’s rolled are hits
If you allowed 2 guns per territ to fire your doubling the chances to kill the planes, with Units that only cost 6 IPC’s. It would be too easy to buy a bunch of AA guns and put them everywhere