The airline, no stranger to an IT glitch, says it has now restored key flight plan systems that failed as the Christmas rush gets underway.
British Airways has apologised to customers after suffering "a technical issue" with its flight planning systems that has affected flights departing the US and elsewhere globally ahead of Christmas.
BA said it had fixed the glitch, first experienced overnight, that had grounded many long haul services ahead of scheduled departures and left many passengers complaining via social media.
Among them, possibly, was the actress Liz Hurley who said via her Twitter account that she had been stranded in Antigua for 20 hours "with no food or water, taxis or hotels offered yet".
Sky News was seeking additional information on the extent of the continuing disruption at the airline, which has a chequered recent history for IT reliability.
It is understood that dozens of flights have been delayed and a small number of cancellations.
The latest IT crash for BA came to light when passengers due to depart the USA reported widespread delays and a lack of information from BA staff on the ground.
Some customers said they had been held up for hours.
"All fun and games at JFK," one tweeted. "All British Airways flights grounded due to an error with their flight mapping system and now we have multiple alarms going off in departures."
Another said: "Captain of our British Airways flight just said that their flight computers have been down for two hours worldwide and no BA plane can file a flight plan? Seems not ideal."
Another passenger complained about the uncertainty of the situation: "Midnight and we can't go to a hotel because BA won't officially cancel the flight. We don't know when the flight will leave and there's a plane full of people that they flew from Cayman *after* this meltdown started who will spend the night in the plane!"
BA said the technical issue did not affect any departed flights or short haul services. It also said the failure was not a safety issue.
The airline revealed at 0815 that services were getting back to normal.
"Our teams have now resolved a temporary issue that affected some of our long-haul flight planning systems overnight, which resulted in delays to our schedule.
"We're sorry for the disruption caused to our customers' travel plans."
BA is no stranger to problems with its IT systems following a number of high profile failures in recent years that have damaged the carrier's reputation and its recovery from the COVID
The latest came in March and caused delays at London's Heathrow airport.
Just a month earlier, hundreds of flights were delayed or cancelled due to an IT glitch, exacerbated by staff shortages.