There are at least three potential issues I can identify from your concern. First, I’ll address the regulations/laws on the use of drones or unmanned aircrafts. The FAA provides guidelines and regulations on the use of drones. These guidelines and regulations are detailed, lengthy, and difficult at best to read. In a nutshell, the FAA regulations make a clear distinction between privately operated and commercially operated drone use. Private operators are advised to operate a drone in a safe environment, under 400 feet (AGL-Above ground level), within line of sight of the drone and outside of two miles from an airfield. Drones used for commercial operation must be registered with the FAA and may only be operated by an operator licensed to land a manned aircraft (Aircraft Pilot).
The FAA is not a law enforcement agency. They do not have enforcement powers over the regulations they set; therefore, state and local agencies must adopt and/or pass laws to define the scope of enforcement within their jurisdiction. It is my understanding that currently state law only addresses the use of drones by government agencies. In short government agencies are prohibited from using drones without first obtaining a search warrant, unless there is a situation of life and/or death; such as a large natural disaster.
As far as looking into your windows, assuming there is some sort of camera system onboard the drone, laws for photographing from a public area would most likely come into play. As long as the camera is on or over a public area, or over the operator’s private property, it is my understanding that photographs may be taken. This would be similar to people walking on the street or sidewalk taking pictures of your house or windows, or in any direction for that matter. However, it is not permissible for anyone or a drone to enter your property or property of another’s to take photographs of your property. So, if the drone is flying “around” your house, there may be in issue of trespassing once it enters someone else’s or your property.
Additionally, the operation of a drone near and around your property, as well as your neighbor’s property may fall under local “Public Nuisance” laws. Public nuisance, specifically related to noise, must raise to the level of “unreasonable disturbance or interfere with peace, comfort and repose of owners or possessors of real property.” Law enforcement can immediately address this drone situation if it meets these criteria. It sounds like this may be the case. If so, call 911 and an officer will be dispatched to your location to help address this situation. It may mean educating the drone operator, or it may be a situation where enforcement is reasonable for the specific situation.
I’ve attached a link that may help provide you with additional information. I hope this helps to answer your question.