Hundreds of flights at major airports across Britain were delayed or cancelled on Tuesday after a technical issue at air traffic control provider National Air Traffic Services (NATS) disrupted its flight processing systems. The problem affected operations at Heathrow, Gatwick, Manchester, Stansted and several other airports.
While flights continued to take off and British airspace remained open, the technical glitch resulted in widespread delays. NATS later said it had introduced a fix and that its systems were beginning to recover.
NATS initially said the disruption had been traced to its flight processing system, with engineers working to restore normal operations.
"We have identified that the issue was in our flight processing system. Our engineers are on site and working urgently to resume normal operations as quickly as possible," NATS said in a statement, as quoted by Reuters. "Flights are still departing and airspace is open, but recovery will take some time," it added.
Heathrow, the UK's busiest airport, said it was working with NATS to address the problem. Flight-tracking platform Flightradar24 reported that arrivals and departures were being regulated at airports across the London flight information region because of the technical issue.
The disruption soon led to a large number of delays and cancellations. Data from FlightAware showed that around 100 flights had been cancelled at Heathrow, while another 367 were delayed.
At Gatwick, approximately 250 flights were delayed, representing around 31% of the airport's total operations. By Tuesday afternoon, nearly 300 cancellations had been recorded across the affected airports as NATS systems began recovering.
The impact was not limited to airports in London. Edinburgh Airport warned travellers that the technical problem could affect its operations, while Dublin Airport said flights to and from Britain were also being disrupted. Luton and Birmingham airports, as well as Aberdeen and Glasgow, also reported delays and cancellations.
Airlines were forced to modify their schedules as a result. British Airways said its operations had been affected by the NATS disruption.
"This is entirely out of our control, and we're in touch with our customers whilst our teams work to get them on their way as quickly as possible," the airline said in a statement cited by Reuters.
EasyJet said the technical issue was leading to delays across Europe. British Airways accounted for 96 of the reported cancellations, followed by easyJet with 92, KLM with 20, Lufthansa with 12 and Swiss with 11.
The latest disruption follows previous technical failures that have caused significant problems across Britain's aviation network. In 2024, the UK's aviation regulator said NATS needed to improve its contingency arrangements after a flight-plan processing failure the previous year resulted in widespread disruption.
Airline executives estimated that the earlier incident cost the industry more than £100 million in refunds and compensation. A separate radar-related technical problem in July last year also disrupted flights at Heathrow and other major airports for more than four hours.
NATS later announced that efforts to restore its systems were progressing. "We have implemented a fix and our flight system is starting to recover," the organisation said in a post on X.
Airlines and airports will now have to clear the backlog of cancelled and delayed services, meaning passengers could continue to experience disruptions as flight schedules are gradually restored.
