To move the actiona round a little bit and breakup the evil hoard eveyone always complains about.
How about a field supply limit?
Each field has X # of points. Each time you take off from the field, your plane (or GV) based on its ENY will reduce the supply point pool. Sucessfully landing your plane puts those points back in the pool. The pool is resupplied similarly to fuel/ord/troops/etc... Tie the supply points to the City perhaps? Or add a new generic factory strat. Make it manually resupplyable (not sure if that is even a word, but you get the idea) by goons and m3's using airfield supplies.
This would encourage people to actually attempt to land their plane, encourage them to fly away from the hoarde where the supply situation is a little bit better, and heaven forbid add a little bit realism (runs in fear of the "this is a game" crowd) How many airfields had an unlimited supply of planes parked in their hangars?