The Ministry of Defence has denied claims that a military aircraft caused a major air traffic control failure that grounded thousands of flights.
A report in the Financial Times alleged the disruption began after a flight plan was filed by a British military aircraft, triggering a system fault in the National Air Traffic Services (Nats) network.
An MoD spokesperson said: "We do not believe there's any indication of an error on the part of the military.
"Because it's subject to a live Nats investigation, which is expected to conclude next week, it would be inappropriate for us to comment any further while that investigation is ongoing."
Nats, which manages the UK’s air traffic control and is partly government-owned, has not yet confirmed the cause of the outage.
A Nats spokesperson said: "It would be wrong to speculate while that work continues."
The failure, which occurred on Tuesday (September 8), led to four hours of grounded flights, affecting major airports including Heathrow, Gatwick, Luton, and Glasgow.
More than 2,000 flights were cancelled, and hundreds of thousands of passengers faced delays.
Transport Secretary Heidi Alexander has ordered an independent investigation by the Civil Aviation Authority, alongside the ongoing Nats inquiry.
She said: "I do not believe this issue was unavoidable."
Airlines are not necessarily liable to compensate passengers for disruption caused by air traffic control.
Nats has apologised for its third major technical fault in three years.
In 2023, a computer failure during the August bank holiday caused travel chaos for 700,000 people, while a smaller outage in 2025 caused 150 flight cancellations.
Nats is structured as a public-private partnership.
The government holds a 49% stake, with the remainder owned by a consortium of UK airlines—including British Airways, easyJet, and Virgin Atlantic—alongside Heathrow Airport and Nats employees.
The Nats investigation is expected to conclude next week.
Were you affected by the airport flight disruption earlier in the week? Let us know in the comments.
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