Thousands of airline passengers have woken up far from where they intended to be after dozens of flights to and from Gatwick airport were cancelled.
Many more services have been cancelled on Thursday morning as airlines struggle to get planes, pilots and cabin crew back into position.
The worst-affected services are those involving aircraft that were due to fly out on Wednesday evening.
Norwegian cancelled a round-trip from Gatwick to New York. Thursday’s 10am departure to JFK has been delayed to 9pm.
Problems with the air-traffic control system on Wednesday led to the world’s busiest runway being closed for almost two hours from 5.08pm.
Gatwick has the busiest runway in the world, with a take-off or landing every 80 seconds at peak times.
Arrivals and departures are handled by Air Navigation Solutions (ANS), a subsidiary of the German organisation Deutsche Flugsicherung, rather than the main UK provider, Nats.
A spokesperson for the airport said on Wednesday night: “Flights have resumed at Gatwick following an earlier issue with the systems operated by ANS in our air traffic control tower.
“As we move back into full operations, we are likely to see some delays and further cancellations this evening.
“We apologise to passengers who have been affected and are aiming to operate a full schedule of flights tomorrow.
“We continue to advise all passengers travelling tonight or tomorrow to check the status of their flight with their airline before travelling to the airport.”
Shortly before Christmas, Gatwick airport was closed for 33 hours, disrupting the plans of 160,000 passengers, because of unauthorised drone activity.