I bet this was the cause:-

The cops have recovered a "damaged" drone from near Gatwick.

That was probably what started all the “scare” sightings.

Have you seen the video of a drone flying over there?

There was also a chap who said he saw a bloke in a hi-viz vest packing two drones away and beating it on a bike.

https://www.independent.co.uk/news/uk/home-news/gatwick-drones-never-existed-sussex-police-investiga...

Mr Tingley said one of the “working theories” was that the damaged drone found close to the airport in Sussex was responsible for causing the disruption

Police do not have any footage of the flying machines at the airfield and are relying on accounts from witnesses and the discovery of a damaged device.

I wouldn’t be surprised if it was the police UAVs, (drones), that people saw - there were a number of them flying whilst searching for the rogue drones.

This is the same police force that reported having found knives and knuckle dusters at the Amex last season but when challenged had to admit that the report was an “error”.

Sussex police don’t inspire a lot of confidence.  Why did it take them 36 hours to rule out the couple they arrested?

 government plans new anti-drone measures following successful trial :

Failing that,Plan B :