Flight delays will continue on Wednesday after an air traffic control problem in the UK cancelled nearly 2,000 flights.
Tens of thousands of passengers have been hit with disruption which saw 291 flights cancelled on Wednesday after 1,750 flights were axed on Tuesday, according to aviation analytics firm Cirium.
Nats, the air traffic control provider, blamed a technical glitch and its boss Martin Rolfe apologised, saying there would be a full investigation after the firm admitted resolving the issue had taken “longer than hoped”.
Foreign Secretary Ed Miliband said the outage was “unacceptable” and Transport Secretary Heidi Alexander has summoned Rolfe to a meeting to explain what happened.
Tuesday’s incident marks the third time in as many years that Nats has suffered a technical issues, following outages in 2023 and 2025.
Flyers have been advised to continue checking flights with their airlines as it is expected it will take days for flights to fully resume.
Heathrow has said passengers should only travel to the airport if they have a confirmed flight operating.
With few aircraft able to take off, it is understood landings were restricted, leading to some flights being unable to depart overseas airports.
The fault was widespread across the UK and beyond, with airports in Ireland also reporting disruption.
According to FlightRadar, the worst affected airports were Heathrow, Gatwick, Manchester, and Birmingham.
At Heathrow, one of the busiest airports in Europe, departures were initially paused around lunchtime on Tuesday. Traffic then resumed, before facing further disruption in the afternoon.
Manchester, Luton, Stansted, Bristol, and Belfast City Airports all said on Wednesday that flights had resumed but there continued to be knock-on affects.
A Heathrow spokesperson said on Wednesday its “operations are recovering”.
“Flights are operating today, but we are expecting knock-on impacts as aircraft and crew reposition.”
At Gatwick, a spokesperson said: “Flights have now resumed from London Gatwick. However, we still anticipate that it will take time for our operations to fully return to normal.”
It is not the first time disruption has blighted Nats’ control system. In 2023, a computer shutdown over the August bank holiday weekend caused chaos for 700,000 passengers.
It took an engineer, who had been unable to correct the fault from home, three hours to get to work.
There was another, smaller Nats outage in 2025, which caused 150 cancellations.
Ryanair and Wizz Air have called for an overhaul of Nats, with Wizz Air saying it was “not fit for purpose” in its current form.
Yvonne Moynihan, managing director of Wizz Air UK, reiterated her calls for Rolfe, who has been in charge of Nats since May 2015, to consider his job.
“I think in any position where you’ve had three failures you need to consider three strikes and your out,” she told the BBC.
Rolfe was paid £1.4m for the year ended 31 March, including a £343,000 bonus.
Asked about his future in charge of the company, Rolfe told the BBC there would be “lots of time for that later” but his focus now was on making sure the problem was solved.
Nats is a public-private partnership, 49% of which is owned by the UK government. The rest is split between a group of UK airlines including BA, easyJet and Virgin Atlantic as well as Heathrow and Nats staff.
Rolfe said that despite the current situation, the UK generally had a very good air traffic system.
“Not to take away any of the frustrations and disappointment from people who haven’t been able to travel, but we do have one of the best systems and one of the best services in the world and that’s consistently recognised globally,” he said.
However, Doug Maclean, Nats’ former air traffic control manager, told the BBC that the system’s technological excellence was undermined by repeated outages.
“You’ve got a world-leading system where the wheels fall off every now and again,” he said.
Phil White from Bexhill told BBC Your Voice that his flight to Lanzarote boarded on time but he was left sitting on the tarmac at Gatwick for hours.
“We’ve been told the radar is down and we can’t take off,” Phil said on Tuesday.
“It’s comfortable enough but the pilots been on every 20 minutes saying they are waiting for information from air traffic control and when he finds anything out he will let us know.”
Even if Nats has resolved the issue with its flight processing system, the disruption is likely to persist due to backlogs.
Rolfe said the issue was in Nats’ flight data processing system. He said it was not the same system that failed during the incident in 2023.
Although the technical issue affected departures, arrivals were also hit as space on the ground became increasingly restricted.
Additional reporting by Emer Moreau, Faarea Masud and Nick Watt
