"Following reports of two drones flying over the airfield, we had to suspend flights while this is investigate".
It added an apology, saying passenger and staff safety was its "foremost priority".
Gatwick said two drones had been spotted over the airfield at 9:03 p.m., local time, and there were "multiple reports of sightings" since.
One tweeter said: "Dear @British_Airways thanks for diverting our plan to Stansted and now Heathrow (even though we were meant to land at Gatwick) and now you're not even letting us off the plane".
Flights into Gatwick Airport, south of London, were diverted to other cities across the country while passengers waiting to take off faced long delays just days ahead of Christmas, the UK's Press Association news agency reported.
The airport normally operates throughout the night but the number of flights is restricted because of noise limitations.
Suspected gas explosion destroys eatery in Japan, hurts 42
The two-story wooden building, which also housed a clinic, was seriously damaged, a Sapporo fire department official told AFP. However, the DFA cited media reports which said that the explosion might have been caused by a gas leak.
An increase in near collisions by unmanned aircraft and commercial jets has fueled safety concerns in the aviation industry in recent years.
In Britain, the number of near misses between private drones and aircraft more than tripled between 2015 and 2017, with 92 incidents recorded a year ago, according to the U.K. Airprox Board.
British Airways confirmed: "Gatwick has stopped all arrivals and departures due to a drone, we've been told".
The airline said earlier that the situation was not within its control.
Gatwick added that airlines had been working to provide delayed and diverted passenger with hotel accommodation or transport.