A glitch with air traffic control service, NATS’, flight processing system on Tuesday 8 September led to airlines having to cancel thousands of flights both to and from the UK.
Around 2,163 flights were affected with around 300,000 passengers being impacted, as reported by aviation analytics firm, Cirium. According to FlightRadar, the worst affected airports were Heathrow, Gatwick, Manchester and Birmingham.
The disruption began at approximately 1pm on Tuesday, with a glitch in the flight processing system at NATS' Swanwick Centre in Hampshire. This system processes flight plans and operational information used by controllers to manage air traffic, continually updating flight information as aircraft move through UK airspace - helping controllers maintain a safe flow of traffic.
By around 7pm, when NATS said the system issue had been resolved and it was working to clear the backlog of flights, most flights scheduled to depart earlier in the day had not yet taken off.
By Wednesday evening, the number of flights that had been cancelled or failed to take off since the fault first emerged had grown to more than 2,000, as claimed by Cirium.
The knock-on effects hit flights across Europe, according to easyJet, with some inbound flights scheduled to depart were yet to take off. The disruption spread to include incoming flights to much of southern England, with cancellations and delays continuing throughout the evening.
NATS provides air traffic control services to 15 UK airports. Martin Rolfe, who has led NATS for 11 years, expressed his sympathies to everyone affected by the disruption and revealed that, while NATS take full responsibility for the upheaval, these interferences are rare.
NATS is a public-private partnership, with the government holding the controlling stake of 49%. The rest is split between a group of UK airlines including BA, easyJet and Virgin Atlantic as well as Heathrow and Nats staff.
Downing Street has said that NATS must report back within a week and explain what went wrong during the incident. Transport Secretary, Heidi Alexander, told the House of Commons that she had ordered an independent investigation by the Civil Aviation Authority (CAA). After meeting with Rolfe, Alexander said that a cyber-attack could be ruled out, but that the issue was unavoidable and tough questions need to be asked about resilience of NATS systems.
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. There was another, smaller Nats outage in 2025, which caused 150 cancellations.
The CAA, which is conducting an independent review, has told passengers that the disruption is likely to be considered the result of extraordinary circumstances under passenger rights rules, meaning that passengers were unlikely to be entitled to compensation for delays or cancellations.