It seems that flying drones where I live cannot be done on weekends when the weather is excellent for flying ... clear, no wind. Sea planes and ultralights fly over the tree tops at such low altitudes that you can’t see them until they are directly overhead. You literally hear them well before they are out from behind tall tree cover. I need to fly no higher than local trees (up to 120’) to avoid becoming a hazard. What restrictions do sea planes or ultralights have? Do they have a 500’ low level floor or not? What good is the FAA ceiling of 400’ in this situation?