The technical issue in the control tower, which has now been resolved, meant that flights were unable to take off or land at the West Sussex airport for some time.
EasyJet said one of its flights had been en route to Gatwick prior to the disruption and was diverted to London Luton Airport.
The airline said the rerouted flight will continue to its original destination.
A Gatwick Airport spokesperson said the diversions were the result of “IT issues in the air traffic control tower this morning”.
Earlier IT issues in the Air Traffic Control tower this morning have been resolved and flights are arriving and departing the airport as normal.
Some flights may still experience delays and we advise you to check the status of your flight with your airline. https://t.co/YU90yEER2i
— Gatwick Airport LGW (@Gatwick_Airport) January 6, 2022
They later added: “Earlier IT issues in the air traffic control tower this morning have been resolved and flights are arriving and departing as normal.
“Some flights may still experience delays however and passengers are advised to check their flight status with the airline.”
An easyJet spokesperson said: “Whilst this is out of our control, we apologise for the inconvenience caused by the diversion and delays and would like to thank passengers for their patience and co-operation.
“The safety and security of its passengers and crew is our highest priority.”