Massive disruption hits UK airports after air traffic control issue

By Rhea Mogul, Sana Noor Haq, CNN

(CNN) — Major disruption was expected to continue at British airports on Wednesday –– including Heathrow, one of Europe’s busiest hubs –– after an hours-long air traffic control outage triggered widespread delays and cancellations.

On Tuesday, departure boards at London airports Heathrow, Gatwick and Stansted showed dozens of flights delayed or canceled. Other airports, including Manchester, also reported disruption.

The issue caused some 1,300 cancellations to or from airports in the UK on Tuesday, according to aircraft tracker Flightradar24.

“177 flights have been canceled so far on Wednesday, nearly all at London-Heathrow,” it said.

On Wednesday morning, Heathrow said flights “are operating” but disruptions may continue as airlines “reposition aircraft and crew.” It warned travelers to check with their airline before traveling. Gatwick airport issued a similar statement a short time later.

Heathrow is the world’s seventh-busiest airport by passenger traffic in 2025, according to data from the Airports Council International. More than 84 million people passed through last year.

This is not the first time in recent years that a major outage has affected passengers at Heathrow and other UK airports.

In August 2023, several UK airports and airlines were forced to cancel hundreds of departures and flight arrivals on the final day of the summer public holiday weekend after a major glitch beset NATS, the leading national provider of air traffic control services.

Several budget airlines condemned NATS’ delay in resolving the disruptions this week and called on senior leadership for a major overhaul. UK Transport Secretary Heidi Alexander summoned the chief executive of NATS, Martin Rolfe, for a meeting Wednesday.

Irish budget airline Ryanair said 65,000 of its passengers had been disrupted by the issue on Tuesday and that it had canceled more than 50 scheduled flights.

British Airways, the UK’s flag carrier, had “no choice” but to cancel more than 190 flights, the airline said on a social media post Wednesday.

The company that runs the affected system said on Tuesday that the issue had been fixed, but delays at airports remain ongoing.

The recovery from the issue “has taken longer than we had hoped,” NATS said in a statement.

“We know this is hugely frustrating and apologise unreservedly,” NATS said, adding it is now operating normally and working to clear the backlog of flights.

‘Like trying to get out of Alcatraz’

Social media was flooded with passengers expressing frustrations and sharing photos of massive crowds snaking through airport halls.

One X user called it the “single most stressful and disappointing experience” they’ve had with any transport, adding British Airways offered a replacement “24 hour 4 flight transit for a 2 and a half hour flight to Rome.”

Josie Donoghue was stuck on a plane for three hours at Gatwick airport, before her Ryanair flight to Ireland was canceled, according to the Associated Press news agency.

“Getting through that airport was like trying to get out of Alcatraz,” she told the news agency, referring to the former island prison in San Francisco Bay. “It’s just an absolute nightmare down there. It’s the only word I can use to describe it.”

Some on social media also praised the ground staff for their help during the chaotic situation.

Knock-on effects have been felt in other countries too.

Air India said in a statement on X that the outage has forced India’s flagship carrier to “divert, delay or cancel multiple flights scheduled to operate to and from UK airports.”

Qatar Airways also warned of delays and potential re-routing of flights to and from the UK.

In a statement Tuesday, Ryanair’s chief operating officer Neal McMahon called for NATS’ Rolfe to resign.

Referring to the 2023 choas, McMahon said: “Families travelling on holiday, people travelling for work and thousands of visitors to the UK have once again paid the price for NATS’ abhorrent failure.”

“A critical national infrastructure provider should not repeatedly ​bring the aviation system ⁠to a standstill. NATS is simply not fit for purpose in its current form,” a spokesperson for Wizz Air, a European low-cost carrier, said, per Reuters.

Faced with the criticism, Rolfe defended his organization, telling public broadcaster the BBC that NATS’ systems are fit for purpose, and apologized for Tuesday’s issue.

“Whilst we never want these things to happen – and I absolutely apologize for the fact it has happened today – I do think we’re fit for purpose,” he said.

Since that 2023 incident, UK airports have endured major outages on a yearly basis.

Last year, Heathrow was shut down after a “significant power outage” caused by a large fire nearby. The closure caused travel chaos across the world, upending travelers’ plans with thousands of flights affected. The financial losses from the shutdown were expected to be in the hundreds of millions of pounds.

And in 2024, a global IT software crash caused widespread delays and operational issues at airports worldwide, including those in the UK.

This is a developing story and will be updated.

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CNN’s Issy Ronald, Caitlin Danahar, Rob North, Billy Stockwell and Clare Sebastian contributed to this report.