[dumbguy]

One word, birds. We hit them frequently, and a goose weighs a lot more than most drones. This is panicking over shark attacks while commuting in your car while smoking cigarettes. Sure we need to set limits, but most of this is FUD.

[WalterBright]

Yeah, but drones are harder than geese. I would speculate that one could easily break an engine, and smash out the cockpit windshield. I doubt it would cause critical structural damage otherwise, but it would be illuminating to do some tests (bird strike tests are done).

One possibility is to limit the weight of the drones, which will limit the damage they can inflict.