British Airways has apologized after flights due to depart from the US were grounded for several hours.
The airline said a technical issue that affected some of its long-haul flight planning systems overnight had now been resolved.
BA passengers reported waiting for several hours in airports, with flights eventually departing after long delays.
A spokesman for the airline said the company was “sorry for the disruption caused to our customers’ travel plans”.
There were long delays on long-haul flights, including those between London’s Heathrow Airport and the US and Canada, and other flights serving Gatwick airport, including arrivals from Cancun, Mexico.
“We have additional colleagues on hand to support passengers and get them on their journeys as quickly as possible,” a spokesperson for the airport said.
Passengers had taken to Twitter to report waiting at John F Kennedy International Airport for more than three hours.
Others said they had been sitting on planes parked on runways for hours, before being moved back to the airport.