They have a similar system in Fighter Ace.
Factories produce parts to build all vehicles, and plants produce ammunition and weapons for the planes/vehicles and troops.
Now, there's a "tick" every now and then (forgot the exact time, as I haven't played FA in more than a year), and each tick produces said equipment.
If you lose a factory, you can't have vehicles. And if you lose a plant, you don't have as much ammo for your planes.
It's a good system, but for AH, it would need serious tweaking. Factories for planes would be necessary, and for the late-war power planes, more time would be needed to make them.
Take a 109G-6. Say it takes, oh, a minute to make 25 from a single factory. Now, take a P-51D. That would take a minute to make 10 from a single factory.
It's a rough idea, and if it were to be implemented into gameplay, I'm sure it would be fine-tuned.