A technical failure in the system used to process flights through UK airspace is causing widespread disruption at airports across Britain. National Air Traffic Services ( NATS) first acknowledged a technical problem at 1:46 PM BST (8:46 AM EST) on Tuesday, before confirming at 3:25 PM that it had identified an issue in its flight processing system. UK airspace remains open and flights are still departing, but at constrained rates.

Reuters reports that the disruption is already significant. Ryanair says around 65,000 of its passengers have already been affected, while a live Flightradar24 snapshot shortly after 5:30 PM BST showed that nine of the world’s ten most disrupted airports for departures were in the UK. The incident also comes only three years after a catastrophic NATS flight-processing failure affected more than 700,000 passengers, and little more than a year after another nationwide disruption in July 2025.

Current Status of the NATS System Failure

Credit: NATS

NATS has provided relatively little technical information so far. Its initial statement said engineers were investigating an unspecified issue affecting departures. At 3:25 PM, it confirmed the problem was in its flight processing system and said engineers were working urgently to restore normal operations. AP News reports that departures at some London airports were stopped for around 40 minutes, briefly restarted and then restricted again after the problem recurred.

The largest airports are all reporting significant delays and cancellations, while British Airways has said that it is “experiencing some flight disruption.” easyJet warned that the UK failure was now creating delays across Europe, and preventing many flights from operating, with departures completely halted at its largest base at London Gatwick Airport (LGW). Meanwhile, NATS has stressed that this is not a full closure of UK airspace, saying:

“Flights are still departing and airspace is open, but recovery will take some time.”

Some airlines have been considerably less restrained. Wizz Air said it was “extremely disappointed,” arguing that the organization responsible for critical national infrastructure is “not fit for purpose” as it has repeatedly brought Britain’s aviation system to a standstill. Ryanair, true to its outspoken form, has called for NATS chief executive Martin Rolfe to resign, echoing its fierce criticism following the 2023 failure. COO Neal McMahon shared the following:

“How many more failures do passengers have to suffer before overpaid failure NATS CEO, Martin Rolfe, accepts responsibility for his repeated mismanagement and resigns? Over three years after NATS’ catastrophic 2023 system meltdown, it’s clear that nothing has changed, with UK passengers once again suffering avoidable ATC delays of up to 8 hours today. The astonishing part is that NATS continues to charge airlines and passengers more each year while delivering a worse service.”

Even fixing the affected system will not instantly restore the schedule, and things are likely to get worse before they get better. Eurocontrol restrictions have limited traffic through London, southern England and Wales, while some aircraft bound for Britain have been held at their departure airports rather than adding to congestion in UK airspace. Airlines must then clear delayed departures and recover aircraft and crews that are increasingly out of position — precisely the problem that caused ongoing disruption long after the 2023 technical fault had been fixed.

The Impact Of The Disruption

Credit: Ceri Breeze | Shutterstock

The scale of the disruption is particularly visible in Flightradar24’s live airport disruption index, which combines the percentage of delayed flights, average delay, and cancellations, into a score between zero and five. In a snapshot shortly after 5:30 PM BST, nine of the world’s ten highest-scoring airports for departures were in the UK. A deeper look at data from FlightAware also showed the cancellations at these airports continuing to climb:

Note: Data is a snapshot from 5.30 PM BST, and will continue to change.

At the time of writing, Gatwick, Birmingham International Airport (BHX) and East Midlands Airport (EMA) were the most disrupted, with all having reached the maximum 5.0 rating, which Flightradar24 classifies as indicating major problems. Gatwick was particularly badly affected, with every tracked departure delayed, and an average delay of 100 minutes. Birmingham’s average delay was even longer at 107 minutes.

London Heathrow Airport (LHR) ranked lower on the index, but its much greater traffic volume means the absolute impact is more substantial. It is already approaching 100 flight cancellations, and the ripple effect caused at the UK’s primary international gateway is likely to be larger and longer-lasting.

The effects are also escaping Britain’s borders, with easyJet reporting extensive delays across its European network, and having accumulated over 140 cancellations at the time of writing. This includes growing restrictions on inbound traffic, with aircraft being held before departing for the UK. That creates the prospect of today’s disruption increasingly affecting later rotations elsewhere in Europe and spilling over into tomorrow, even if NATS succeeds in restoring normal traffic flows during the evening.

NATS Has Been Here Before

Credit: Nigel Harris | Shutterstock

If this is all feeling very familiar, it’s because it is. The closest precedent came on August 28, 2023, when NATS’ automated flight processing system encountered a flight plan containing two separate waypoints carrying the same identifier. The primary system generated a critical exception and entered fail-safe mode; because the “backup” processed the same flight plan using the same logic, it failed as well. Around 1,500 flights were canceled that day as automated flight-plan processing was severely curtailed.

The consequences went far beyond August 28. The Civil Aviation Authority (CAA) conducted an independent review, and estimated that more than 700,000 passengers were affected — around 300,000 by cancellations, 95,000 by delays exceeding three hours and more than 300,000 by shorter delays. Airline schedules took days to recover, and the CAA ultimately issued 34 recommendations covering resilience, contingency planning, engineering resources and industry response. All outstanding recommendations from that review were formally closed by the regulator on June 19, 2026, less than three months before today’s failure.

Another failure followed on July 30, 2025, although it involved a different part of the infrastructure. A radar-related technical problem at NATS’ Swanwick control center reduced traffic flows for several hours before controllers switched to a backup system. Cirium counted 122 cancellations by that evening, while further Heathrow cancellations followed the next morning as airlines worked to return aircraft and crews to their scheduled positions.

There is currently no evidence that today’s technical issue has the same cause as the 2023 failure, and it would be premature to assume it will reach anything approaching that scale. However, the earlier events demonstrated how quickly a few hours of severely constrained air traffic control capacity can turn into several days of airline disruption. With NATS warning that recovery will take time, the key numbers to watch now are not simply today’s delays, but the rate at which cancellations accumulate and whether aircraft and crews can be restored to position before Wednesday’s first wave of departures.

NATS advises passengers to check the status of their flight with their airline. It will provide ongoing updates here.