Better yet
Planes/gvs supplied by fuel at fields.
Fuel at field goes down. Stays down for X amount of time.
Fuel at fields is supplied by several different fuel depots (lets say 2)
Killing one depot has little to no effect on resupply to base. Killing both has the effect of fuel staying down for XX amount of time. Provided nobody manually resupplies
Fuel at Depots is supplied by fuel factories (Again more then 1)
Now if Fuel depots are porked and fuel factories are porked then fuel at effected feild/s says down for XXX Time and so on and so forth.
Also the farther up the chain you go the more heavily defended by AAA they should be so that by the time you reach a factory, you should be able to walk on the amount of Flat that is thrown up.
No bombing raid on a major factory or HQ should be a cakewalk.
Same thing should hold true for everything else, Ammo, Troops, Dar etc.
Kinda like a pyramid scheme.. but different.
