British Airways has apologised after flights due to depart from the US were grounded for several hours.
The airline said it was urgently investigating a technical issue with its third-party flight planning supplier.
BA passengers have reported waiting for hours in airports.
The airline said it aimed to get planes departing as quickly as possible, adding it was sorry for any disruption to its customers’ plans.
Passengers have 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.
In a statement, British Airways said: “Our flights due to depart the USA tonight are currently delayed due to a technical issue with our third-party flight planning supplier, which we are urgently investigating.
“We’re sorry for any disruption this will cause to our customers’ plans, our aim is for these flights to depart as quickly as possible.”