Didn't see this posted anywhere, probably because it's not FE related.
But, if these drones were in the air for 14 hours, then there's some super whizz bang battery technology going on!
As many will be aware, some rather strange events have happened over in the UK at Gatwick Airport.
The whole airport was shut down yesterday and at least part of today, because drones have been zooming all over the airport runways.
https://www.bbc.com/news/uk-england-sussex-46623754"Drone sightings kept London Gatwick Airport closed for a second day, derailing trips of tens of thousands of travelers ahead of Christmas, while the military was called up to assist with what local law enforcement called a "deliberate act." Flights were suspended as law enforcement searched for the operator of what it called an "industrial drone." The drones appeared to be "a deliberate attempt to disrupt flights," said a statement from the airport, the second-busiest in the U.K. after London Heathrow. Hundreds of flights were grounded, while scores of others were diverted to other airports. London Gatwick, which serves more than 100,000 passengers a day, said disruptions would continue on Friday."
Military

How difficult would it be, to notice which direction the things are flying in from and, which direction they head back out in when their batteries run low?
Toygrade quads don't have more than a few hundred feet of range and can remain airborne only 5-6 minutes at best.
Posh stuff may have the battery power to stay up for 25 minutes, but they are geofenced...unable to fly at airports anyway. The things will not even take off if near to an airport.
Pics of DJI products are shown in various reports, but those require the owner to register with DJI before flying anywhere. DJI's products being part of why the FAA imposed a multitude of rulings against a formerly wonderfully safe hobby in the past couple of years.
In short, these were not a couple of Walmart bought early Christmas presents being flown around by kids.
Another source:
https://metro.co.uk/2018/12/20/first-footage-drone-evading-police-helicopters-gatwick-airport-8271026/Reports of drones being in the air for 14 hours, either means the drones could have been followed multiple times and the pilot caught on any occasion, or something hinky is going on. The military couldn't spot them, helicopters didn't follow them to the source, 20 police units couldn't spot where the drones took off or landed from? I mean, really?
All of them run on 2.4GHz, simply blast a 500W dirty broadband 'sonic cannon' in the general direction. A man in a shed could have built that yesterday afternoon.
Or, this was why they couldn't find the pilot on the ground!