The Ministry of Defence has rejected reports that a military aircraft was responsible for the air traffic control system failure that grounded more than 2,000 flights and disrupted travel for hundreds of thousands of passengers in the UK this week.
A flight plan submitted by a British military aircraft triggered the outage, according to the Financial Times, which reported on Friday that four sources familiar with the incident said the plan caused a glitch in the system operated by National Air Traffic Services (Nats) on Tuesday. The system took hours to restart, the paper reported.
MoD denies error
A Ministry of Defence spokesperson said: “We do not believe there's any indication of an error on the part of the military.” The spokesperson added that because the matter was subject to a live Nats investigation, expected to conclude next week, it would be “inappropriate” to comment further.
The denial was echoed in statements issued over the weekend, with the MoD saying it could not identify any mistake by the armed forces.
Nats, in which the government has a controlling interest, said it was continuing to investigate the underlying cause. A spokesperson said: “It would be wrong to speculate while that work continues, and a full technical investigation will follow.”
Scale of disruption
The technical failure struck on Tuesday, causing more than 2,000 flights arriving in or departing the UK to be cancelled, with disruption spilling into Wednesday. Hundreds of thousands of passengers were thought to have been affected after the system went down for four hours, affecting airports including Heathrow, Gatwick, Luton and Glasgow.
In Manchester, more than 100 flights were delayed and over a dozen cancelled, according to local reports. Passengers described sitting on planes for more than four hours before take-off.
The Financial Times also reported that Nats operations officer Kathryn Leahy called operations managers at airports and airlines, and that tensions ran high after she informed them that the flight processing system lacked a dedicated backup because Nats was overhauling its systems and duplicating data would cost “vast amounts”.
Political and industry reaction
Transport Secretary Heidi Alexander told MPs on Wednesday that she did not believe the air traffic control issue was “unavoidable.” She had earlier summoned Nats chief executive Martin Rolfe to a meeting and was reported to have given him a week to explain the shutdown.
Alexander also commissioned an independent review by the Civil Aviation Authority, which said passengers were “unlikely to be entitled to compensation for delays or cancellations that were directly caused by the incident.”
Ryanair chief executive Michael O’Leary called for Rolfe to be removed, describing his position as “untenable.” Rolfe has apologised for the incident, saying he took “full responsibility,” and ruled out a cyber-attack, saying the event appeared to be something Nats had “never seen in 50 years of operation.”
A Wizz Air spokesperson expressed disappointment over the disruption, saying: “Nats is simply not fit for purpose in its current form.”
Previous outages
Nats has apologised for its third major technical fault in three years, after a computer shutdown over the August bank holiday in 2023 caused travel chaos for 700,000 people, and a smaller outage in 2025 caused 150 flight cancellations.