Don't know. Hope it does.
Make the drone upgrade PLAYER type, and upgrade a vehicle with a drone. When done, each vehicle should get a drone when one of them buys it. But if you can re-buy it once one of the drones is shot down, then it works. It is also possible that you have to wait for them to shoot ALL the drones down before you can re-buy the upgrade. Try it out and see, I'm interested in the results aswell.