Flights at Gatwick Airport were suspended for about two hours due to an difficulty with its air visitors manipulate systems.
Twenty-eight flights were cancelled and 26 diverted to different airports after the problems started out at about 17:00 BST.
The airport stated it had experienced a problem in its manage tower.
Flights are still behind schedule with the aid of an hour or more, with cancellations anticipated in the course of the evening, Gatwick said.
Some passengers had been stuck between the boarding gate and the plane
The outcomes were felt at airports throughout Europe, with many inbound flights to Gatwick cancelled and others expected to be delayed with the aid of about three hours.
Passengers due to travel to or from the airport have been advised to test for updates with their airline.
EasyJet said if EJU flight status Gatwick was running at a "reduced rate" and apologised for the disruption, which it said was "outside of our control".
A spokesman stated the airport aimed to go back to a complete time table on Thursday with out delays, adding: "The ambition is it need to run as usual."
Staff had told passengers to prepare for delays of up to 4 hours
Colin Franks, who was due to board an EasyJet flight to Palma, Spain, at 18:00 said he was "trapped between the boarding gate and the air bridge".
He said the plane's pilot had spoken to passengers, adding: "He stated they had been given a provisional [take off] time of 10pm.
"At the moment, everyone is speakme to each other and it's pretty cheery. There are lots of kids here."
In December flights have been suspended for 30 hours after drone sightings, inflicting chaos for 140,000 passengers.
A senior Sussex Police officer stated the airport was no longer organized for an attack with the aid of more than one drone.