The real object is to get people into the skys to fight ... remember, it's called "Aces High" ... not "Aces in the Tower".
If I remember correctly, the runway is an object that can be destroyed ... and the arena setting is something like 100,000 lbs of bombs and the regen time is like 1 second.
If you want to close a field down, then take out all the hangers ... but wait, that might be hard to do ... what was I thinking ?