Hundreds of thousands of air passengers faced flight delays or cancellations after a technical issue at the UK air traffic control services provider Nats caused widespread disruption on Tuesday. According to flight monitoring website Flightradar24, over 1,000 flights were cancelled at UK airports by 8pm, with the incident starting around 1pm and affecting major airports including Heathrow and Gatwick.

Nats confirmed it was investigating a technical issue causing disruption to flight departures and later identified the problem in its flight processing system. The company announced a fix was implemented by 4.40pm, but most flights scheduled to depart from London airports and others had yet to take off. The disruption spread to include incoming flights to much of southern England, with cancellations and delays continuing into Tuesday evening.

British Airways stated that the severity of the issue would have a significant knock-on impact, with over 100 flights cancelled or diverted, inconveniencing tens of thousands of customers. Heathrow reported that departures had resumed with disruptions but arrivals were suspended for the rest of the night. Airlines renewed calls for Nats to be overhauled after the third large-scale incident attributed to its systems in over three years.

Ryanair reiterated its demand for Nats chief executive Martin Rolfe to resign, with its chief operating officer, Neal McMahon, calling the failures 'abhorrent.' Wizz Air also criticized Nats, stating that a critical national infrastructure provider should not repeatedly bring the aviation system to a standstill. The transport secretary, Heidi Alexander, acknowledged the technical issue and expressed regret for the inconvenience, stating that technicians were working to resolve it.

Nats spokespersons emphasized that the fault was not the same as previous outages in 2023 and 2025, and that the system was only 'starting to recover.' However, the chief executive, Martin Rolfe, admitted the disruption was significant and that there was a 'huge amount of disruption that’s now built up in the system.' He stated that Nats was working closely with airlines and airports to resolve the situation as quickly as possible.

The incident follows an 'isolated event' a year ago that caused widespread disruption, though it appears less severe than the full grounding of flights in August 2023, which prompted a parliamentary inquiry. British Airways noted that the current disruption would affect operations through Wednesday at least, with passengers offered free rebooking until Friday. The full extent of the impact remains unclear, with some flights across Europe also affected, according to easyJet and Eurocontrol. What remains unknown is the precise nature of the technical issue and whether similar problems could recur in the future.