I think it was Kimmel last night who mentioned one family's experience with their drone sighting.. their car clock changed time and then went back to the correct time. Car clocks, if they're connected to ntp, would be through cellular network. Imagine a drone carrying a stringray cellular tower emulator with enough power to be _the_ tower for an area for a free hours. Now imagine a couple square miles with these in the air. No need to get a subpoena for a telecom, you are the telecom.