The airport advised people flying or collecting someone from Gatwick on Wednesday or Thursday to check the status of their flights.
"Following reports of two drones flying over the airfield, we had to suspend flights while this is investigate".
Gatwick officials said two drone were sighted near the runway.
Queues of passengers in the check in area at Gatwick Airport this morning, as the airport remains closed after drones were spotted over the airfield last night and this morning.
Fraser Hutcheson tweeted: "Had to land at Birmingham airport because #GatwickAirport has been closed due to drone activity".
He criticised the "irresponsible" act and 10,000 people had been affected by the closure, including 2,000 whose flights had been unable to take off.
"If there is anybody at Luton airport that has been diverted from Gatwick airport and needs a lift home, let me know", he wrote on Twitter.More news: US, Canada look to ease strains amid 3-way spat with China
One of Britain's busiest airports has been closed after drones were seen over the airfield, stranding passengers just days before Christmas.
All flights to and from the airport were suspended on Wednesday night with planes being diverted to other United Kingdom airports, including Manchester, Luton and Stanstead.
Crowds of passengers waited inside Gatwick's terminal for updates, while others reported being stuck on waiting planes for several hours.
According to Flight Radar, more than two dozen flights bound for Gatwick had been diverted by 11pm.
Gatwick Airport said airlines were "working to provide affected passengers with hotel accommodation" or provide alternative travel options.
The 27-year-old said passengers were then having to get taxis back to Gatwick after they were finally allowed off the aircraft. "Which has made the delay better".