Airlines stepped up their criticism of Britain's aviation systems Wednesday after a major air traffic control failure stranded hundreds of thousands of passengers, while ministers summoned the head of flight control to explain the shutdown.
Flights resumed at major airports across the country after the hours-long outage Tuesday, which resulted in the cancelation of 2,000 flights and ramped up pressure on air traffic control provider NATS and its boss Martin Rolfe.
Ryanair said NATS had told it that the cause of the shutdown was the same problem behind the last major air traffic outage in 2023, which cost airlines 100 million pounds ($135 million). The carrier has repeatedly called for Rolfe to step down.
Transport minister Heidi Alexander will later Wednesday hear directly from Rolfe after she summoned him to explain the fault, amid concerns over the resilience of the infrastructure and technology.
The NATS shutdown in August 2023 caused travel chaos, and there was also a radar-related technical issue in July 2025, which affected major airports including Britain's largest, Heathrow.
"I am seeking assurances that lessons will be learned and systems that support aviation are up to the job," Alexander said on the social media platform X.
'Absolute rerun' of 2023 meltdown
Michael O'Leary, group CEO of Ryanair, which is Europe's biggest airline, told Reuters the outage was "an absolute rerun" of what happened in 2023, when a rogue flight plan caused the shutdown.
"Fire him. He's been there since 2015. He is useless," he said of Rolfe.
Apologizing to those affected by the issue, Rolfe had earlier said that the problem was not the same as in 2023.
"This will be something different that we've never seen in 50 years of operation," he told BBC Radio, adding that NATS had ruled out a cyberattack.
Aviation analytics company Cirium confirmed about 2,000 flights to and from U.K. airports had been affected by the outage Tuesday and Wednesday combined, with 30% of scheduled departures grounded Tuesday and 5% Wednesday.
Ryanair, which said Britain's air traffic services routinely underperformed those in other European countries, said its losses from Tuesday's outage were 3 million pounds so far, after it canceled 260 flights affecting 48,000 passengers.
British Airways Tuesday canceled or diverted 100 flights with tens of thousands impacted, and said Wednesday 190 flights had been canceled as disruption continued.
As operations restarted, Britain's main airports – including London's major Heathrow and Gatwick hubs – said passengers should check with their airline before heading to the airport as schedules would have changed.
"We are expecting knock-on impacts as aircraft and crew reposition," the U.K.'s busiest hub said in a statement.
NATS, a public-private partnership which is partially owned by airlines including British Airways and easyJet, pension funds and the government, paid its owners dividends of 175 million pounds in 2025.
Ryanair is suing NATS at London's High Court and seeking over 7 million pounds over the 2023 outage and has called on NATS to reinvest its profits into performance improvements and hiring more staff.