The New York Times counted 52 Amazon drones over one Richardson yard in a day. The FAA ruled that noise not significant in July. Here is the paper trail.
The noise came out of nowhere. At first, it was an acute and disturbing buzz, like that of a sailor flying in a dark room at bedtime, and it amplified as it got closer. A family that was lounging in the pool of its back yard in Richardson, Texas, just north of Dallas, could not help but notice it.