nuisance not only for invasion of privacy, but also for the danger if he crashes his stupid drone into your family or vehicles, etc., and for the noise and bothering of your quiet enjoyment of your property. While it's true that you don't own the airspace that big planes fly in, the lowest ceiling is usually 400 feet, so if the drone was lower than that, it's owner can't rely on those laws. IIRC, the common law is that you're entitled to the quiet enjoyment of your property "from heaven to [heck]," so unless a law changes that (e.g., by letting planes fly higher than 400 feet above your property) the guy was probably trespassing with his drone.

I think the cop you talked to was more worried about encouraging you to not get into a firefight in a subdivision than about protecting your family, and I doubt he knows the law. If you have an HOA, this neighbor is probably in violation, and they can stop him. If not, I'd call your lowest governmental body (town/city/county) and complain to them. They should be able to call the local police at that level (town cops/city cops/county cops) and tell them to do their job and investigate.

Where we live, no one would bat an eye if a person outside of city limits shot down a drone buzzing their family.