Passengers flying to and from the West Sussex airport on Saturday (9 December) reported planes being stuck on the tarmac after the problems started at around 8am.
A Gatwick spokesperson said: “There was an outage to a local Nats system which has now been rectified.
“Some passengers may experience delays. We apologise for any inconvenience.”
One flight was reportedly cancelled and two more were diverted while dozens of departures and arrivals were delayed.
A Nats spokesperson issued a statement on Saturday, saying: “For a short period earlier this morning we had a technical issue that was quickly fixed. To make sure safety was maintained departures were paused temporarily but were resumed around 8am.
“We are working with airlines to minimise any delays and would like to apologise for anyone whose journey has been affected.”
It comes three months after there was major disruption to flights across UK airports, including Gatwick and Heathrow, on 28 August after Nats suffered a technical glitch while processing a flight plan.
The combined cost to airlines providing refunds, rebookings, hotel rooms and refreshments to affected passengers was estimated to be around £100 million.
Calling for Nats chief executive Martin Rolfe to quit, Ryanair chief executive Michael O’Leary said on Saturday: “After the August Nats system failure Martin Rolfe claimed it was a one-in-15-million tech glitch.
“Yet here we are again three months later, and UK Nats fails again at Gatwick.
“Thousands of passengers today face long delays, diversions, and cancellations as Nats under Martin Rolfe’s incompetent leadership fails again. It’s time for Martin Rolfe to go.
“If he won’t quit, then transport minister Mark Harper should fire him. These repeated UK Nats system failures are unique to the UK and are not repeated in any other European Air Traffic Control service.”
Rory Boland, Which? Travel editor, added it was “unacceptable” that Gatwick passengers had been hit again by air traffic control issues.
“Though compensation will not be payable as these delays are outside of airlines’ control, carriers must ensure they meet their legal obligations to look after passengers and provide them with support and help with refunds and rerouting, including with other carriers if necessary,” he said.
