LONDON — A failure in the United Kingdom’s air-traffic flight-processing system disrupted travel across major airports on September 8, leading to more than 600 canceled flights and extensive delays before operator NATS said the technical problem had been resolved.
The incident affected Heathrow, Gatwick, Stansted, London City, Manchester, Birmingham and airports in Scotland, with consequences spreading to flights elsewhere in Europe. The Associated Press, citing Flightradar24, reported at least 625 cancellations. The Guardian reported that hundreds of thousands of passengers were affected, while airlines warned that knock-on disruption could continue into September 9.
NATS first acknowledged a technical issue at 1:46 p.m. local time. At 3:25 p.m., it identified the problem as being within its flight-processing system. A fix was implemented at 4:40 p.m., but recovery took longer than expected. In a 7:30 p.m. update, NATS said the system was operating normally while staff worked to clear the backlog.
Airspace stayed open, but schedules collapsed
NATS said UK airspace remained open and some flights continued to depart during the failure. Traffic restrictions and the resulting backlog nevertheless forced airlines and airports to cancel or delay large numbers of flights.
British Airways, easyJet, Ryanair, Wizz Air, KLM and Lufthansa were among the carriers affected. Reuters reported delays or cancellations involving close to 1,000 scheduled arrivals and departures in available tracking data. The precise figures varied during the day as airlines adjusted schedules and recovery began.
Ryanair said more than 65,000 of its passengers were delayed. EasyJet reported at least 137 cancellations by the afternoon, according to The Guardian. Passengers described prolonged waits, time spent aboard aircraft and limited information as airports and airlines worked through the disruption.
Airlines demand accountability
Ryanair called for NATS chief executive Martin Rolfe to resign. Wizz Air argued that NATS required comprehensive reform. Their criticism focused on repeated major disruptions and earlier assurances about system resilience.
NATS apologized without qualification for the disruption and said it was working with airlines and airports on recovery. Its public statements did not identify the root cause beyond the flight-processing system, and they did not describe the specific component or failure sequence.
The UK Civil Aviation Authority contacted NATS for a full incident report and said it would consider whether additional steps were necessary to protect the reliability and resilience of the air-traffic system. Transport Secretary Heidi Alexander also called for work to prevent a recurrence.
Previous failures raise resilience questions
The disruption renewed scrutiny created by significant NATS failures in 2023 and 2024. The 2023 incident was traced to an unusual flight-plan anomaly that caused automated processing to stop and led to thousands of cancellations. Industry estimates placed airline compensation costs from that event above £100 million.
There was no public evidence in the material reviewed that the September 8 event involved a cyberattack, malicious interference or the same technical trigger as the 2023 failure. Characterizing the new outage that way would be premature until NATS and the regulator complete their reviews.
What remains unknown
NATS had not disclosed the detailed root cause, why fallback arrangements did not prevent widespread disruption, or how quickly the backlog would be cleared. Final cancellation and delay totals were also still changing. The regulator’s requested report will be central to determining whether technical, procedural or contingency-plan changes are required.
Sources: NATS operational statements, September 8, 2026; Reuters, Associated Press and The Guardian reporting published September 8, 2026. Counts are attributed because flight totals changed throughout the recovery.
