Thousands of passengers at airports including Heathrow and Gatwick are facing travel chaos due to a “technical issue” that grounded flights across the UK.
Departures were severely delayed because air-traffic chiefs said planes could not take off safely.
But about four hours after the disruption began, the National Air Traffic Control Service (Nats) said engineers had identified the problem and had fixed it.
However, it was not clear how long it would take for systems to return to normal after the widespread delays and cancellations.
A Nats spokesperson apologised for the delays and advised passengers to check with their airline before travelling to airports.
The worst affected airports were Heathrow, Gatwick, Manchester and Birmingham, according to Flightradar24, which said approximately 4 per cent of UK flights had been cancelled or delayed as a result of the issue.
Ryanair and Wizz Air slammed Nats as “not fit for purpose”.
Some passengers were planning to spend the night in airports. One couple had their honeymoon flights cancelled.
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'Is there a maximum time limit we’re expected to sit here?' passengers ask
Passengers complained to British Airways on social media about the disruption.
One wrote: “Stuck on what was supposed to be the 1:20pm flight to JFK and a number of us would like to know what the policy is for either serving food and beverages or allowing passengers to get off the flight?
“Is there a maximum time limit we’re expected to sit here?”
Another said: “Hey @British_Airways — my 3.55pm flight from DUB > LCY has been delayed till 12.30am. At this point, I’d prefer to be booked on another flight later in the week. No staff to talk to here at Dublin, no communication. Anything you can do to help?”
Recovery taking 'longer than hoped' - Nats
Recovery from today’s system issue has taken longer than we had hoped . Our system issue is now resolved, we are operating normally and working as hard as possible to clear the backlog of flights. (1/2) https://t.co/NpFp3PBDo7
— NATS (@NATS) September 8, 2026
Julia Pobegailova, 29, was due to fly from Gatwick to Tel Aviv at around 1.30pm today.
The journalist, who works for an Israeli TV channel, said that after boarding the Wizz Air flight she sat on the runway for three hours before being informed it had been cancelled.
Ms Pobegailova told PA that Wizz Air’s next flight to Tel Aviv was not until Saturday.
“I’m just trying not to panic,” she added.
“I’m trying to figure out what to do and find a solution. There’s always a way, so it’s fine.”
Disruption expected for rest of today at Manchester Airport
Manchester Airport said it expected flight disruption to continue for the rest of the day.
In pictures: Travel plans disrupted
Minister wants lessons to be learnt from chaos
Transport secretary Heidi Alexander said she was seeking assurances that lessons would be learnt following the air-traffic-control issue.
Recovery will 'take time', air traffic chiefs warn
Recovery from disruptions to flights leaving the UK caused by the air-traffic-control issue will “take some time”, Nats has said, after more than 400 flights were cancelled.
Some 425 flights were cancelled to and from UK airports as of 5pm following the issue, flight-monitoring website Flightradar24 said.
Passengers have been advised to check the latest flight information with their airlines, while airports apologised for the disruption caused.
Nats, which provides air-traffic-control services to 15 UK airports, said it was “investigating a technical issue” causing disruption to some flight departures, and later said it had identified the problem was in its “flight processing system”.
BA cancels or diverts at least 100 flights
British Airways said it was forced to cancel or divert more than 100 of its flights on Tuesday following an air-traffic-control issue.
A spokesperson said: “While Nats has informed us that their air-traffic-control system fault has been resolved, the severity of the issue means there will be a significant knock-on impact for customers and colleagues.
“We were forced to cancel or divert more than 100 flights on Tuesday afternoon, inconveniencing tens of thousands of customers.
“This incident was entirely out of our control and incredibly frustrating for our customers and colleagues, with aircraft and crews ending up out of place.
“We ask customers whose flights have been cancelled not to travel to the airport and to bear with us if they’re trying to get in touch, as our call centres are incredibly busy at the moment.”