Plenty of potential in this idea.
If a full railroad system were in place again you could implement a whole new supply dynamic to the game.
Limited number of Field Supplies produced in a certain amount of time at Factory, say 600 an hour. They are also generated by the towns attached to airfields but those supplies are for that field alone - 10 an hour.
Supplies leave factory on railroad network and are delivered 50 at a time until the train is empty.
So 12 Airfields within the factory vicinity are receiving 70 Field Supplies per hour.
Once these supplies are at a field, they can be re-distributed to any other friendly field by C47, M3 etc (obviously more than 1 at a time a goon could hold 5 say). If the player is killed carrying the supplies they revert back to the field of origin (for obvious reasons).
Planes and GV's would have a supply cost as would ord, fuel and troops, though I think Fuel would be a minimal cost. So a 5 ENY plane would cost 3 field supplies. A 20 ENY plane would cost 0.5 field supplies (random figures pulled out of the air). The field can only provide the ride if it has the resources.
This is all just off the top of my head, but with a little work this has the potential to reduce the horde, make strat and supply lines important again, make strategy and resource management part of the game, remove the ability to steam-roller base after base.....
Drunk