Federation Commander

Nothing in the rules (4E) seems to prevent it, and I've always played that way. Just remember that you need to allocate ALL anti-drone fire before rolling to hit for any of them. So If you allocate two anti-drones to one drone, and the first one destroys the drone, you still expend the ammo for the second, and can't use it against another drone in the same impulse.

Optimus has it correct. You can fire two ADDs at a single drone, but both must be declared before the "to hit" rolls are made. If the first hits, the second is wasted... but sometimes, it's worth it just to be sure.