Sussex Police launched an investigation and Gatwick promised to reopen the runway following "suitable reassurance". Flying a drone within 1km of an airport or airfield boundary was made illegal in Britain at the end of July.
Flights at Gatwick Airport have been halted amid reports of drones being flown over the airfield.
Flights were suspended between 9.03pm on 19 December and 3.01am on 20 December.
The airport has issued a warning, suggesting that people departing or picking someone up from Gatwick check the status of their flights.
The runway at London's Gatwick Airport remains closed this morning following reports of drones flying close to the airport - despite briefly reopening overnight.
A spokeswoman added that airlines were working to provide hotel accommodation or transport for those whose flights were diverted.
"We apologise to any affected passengers for this inconvenience but the safety is our foremost priority", it added.
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"Some inbound flights were holding while others had been diverted", BBC said while quoting a spokesperson.
One traveller said on social media his BA flight was being diverted to Stansted.
The airline responded: "Sorry about that, Elly".
Flights due to take off remained parked on the runway, while others scheduled to land at Gatwick were diverted to other airports, according to some passengers who took to Twitter to express their annoyance over the situation. Something that's not within our control.
Passengers reported that some flights were diverted to other United Kingdom airports, including Birmingham, Manchester and Stansted.
Joe Bond's flight from Belfast was diverted to Birmingham.