Hobby drones/model aircraft (weight under 55 pounds) operated for recreation are limited to an altitude of 400 feet above the ground in direct visual sight of the operator and must not operate within five miles of an airport among other restrictions. Under those conditions, it is only required to register the UAV, but not to file a flight plan. If the same drone is operated for money then you need FAA permission.
Clearly the draconian punishments for interfereing with operation of an aircraft, tampering with or damaging one, or interfereing in the flight of one were designed to deter bad actors from endangering large aircraft or their passengers. But a vehicle weighing 55 pounds falling from altitude after having been attacked poses a significant danger as well. The principle is pretty well established that the owner of property does not have the right to control the airspace above his land, and must defer to FAA rules and federal statutes. Perhaps it would be wise to have a law that makes damage to small UAV's without other property damage or injury a lesser offense, but under the current interpretation, the little guys fall under the same law as the big guys. Hold your fire.