NATS System Failure Cancels Over 1,000 UK Flights

A failure in Britain’s air traffic control system on September 8 also hit travelers flying to London through European hubs, as planes bound for the UK were held on the ground across the continent while the disruption played out. Ryanair and Wizz Air, the two budget carriers that fly regularly to both Belgrade and Nis, were among the hardest hit by the incident, and when aircraft and crews fall out of position in one part of a European network, the delays typically spread to the carrier’s other routes as well. The fault itself struck the systems of NATS (National Air Traffic Services), which manages air traffic across all of the United Kingdom.

Heathrow halted all departures at 12:48 local time after NATS identified a problem in the automated system for processing flight plans, known as the Flight Plan Reception Suite Automated Replacement. The operator confirmed at 13:46 that it was investigating the fault, and a fix was not in place until around 16:40, nearly four hours after the first disruption. Even once the fix was applied, airlines warned the fallout would last for days, since aircraft and crews remained out of their normal schedules.

How many flights were actually canceled

Figures on the scale of the disruption vary by source. Combined estimates put the total at more than 1,000 canceled flights. Flight-tracking site Flightradar24 counted at least 625 canceled flights to and from the UK over the course of the day, according to one report, while another source says the same site had logged over 1,000 cancellations by 8 p.m., a figure closer to the overall estimate. FlightAware, for its part, counted 490 delayed or canceled departures and 525 delayed or canceled arrivals at London’s major airports by mid-afternoon.

Besides Heathrow, the disruption also hit Gatwick, Manchester, Stansted, London City, Birmingham, Edinburgh, Bristol and Belfast airports. The biggest airlines released their own figures:

• Ryanair said more than 65,000 passengers were affected, with delays of up to eight hours, and that it had canceled more than 50 flights
• British Airways canceled or diverted more than 100 flights, including at least 16 departures from Heathrow
• easyJet canceled 137 flights
• KLM canceled 26, and Eurowings 22 flights

Blame and calls for a resignation

After the fault was fixed, NATS admitted the failure. The operator’s chief executive, Martin Rolfe, said: “We absolutely take responsibility for this. We never want these things to happen.” NATS added in an official statement: “We are sincerely sorry for the disruption to people’s travel today.”

Airlines were not satisfied with the apology. Ryanair repeated its call for Rolfe to resign, and the airline’s chief operating officer, Neil McMahon, said: “After the 2023 meltdown, we were told lessons would be learned. Yet here we are again.” McMahon added that ordinary families had once again paid the price: “Families traveling on holiday have once again paid the price for NATS’ disgraceful failure.”

Wizz Air went further, saying the operator was no longer capable of doing its job. UK Transport Secretary Heidi Alexander responded with an apology to passengers, while also announcing she was seeking an explanation:

“I know this will be frustrating for passengers and I’m sorry. I am seeking assurances that lessons will be learned.”

The UK’s Civil Aviation Authority (CAA) announced it would request a full incident report from NATS, on the basis of which it will decide whether additional measures are needed to make the air traffic control system more reliable.

Why this keeps happening: the third time in three years

The September 8 failure was not the first of its kind. The same operator suffered a flight-plan processing system outage in August 2023 that cost airlines more than 100 million pounds in compensation and refunds, and in July 2025 it recorded another outage lasting more than four hours. Three major breakdowns in three years are why, this time, airlines are openly calling for a change in leadership rather than settling for the usual apology and a technical report on the cause.

For travelers flying from Serbia, the fallout from a failure like this rarely stays confined to Britain. The aircraft Ryanair and Wizz Air use on routes to the UK belong to the same fleets that serve flights to Belgrade and Nis, so a disrupted schedule in one part of the network typically produces delays on other routes in the days that follow. The same holds for passengers flying to London via European hubs such as Amsterdam, where KLM was canceling flights directly because of this failure.

It has not yet been said when the Civil Aviation Authority will receive the report it has requested, or whether it will lead to a concrete change at the top of NATS.