Flights were delayed or cancelled across several airports in the UK on Monday, Sept. 21. Manchester, Edinburgh, Glasgow and Belfast all reported delays and cancellations after an air traffic control disruption. The National Air Traffic Services (NATS) stated that anything south of Manchester would be “broadly unaffected,” although London City reported some delays.
A ‘connectivity issue’ is to blame
The problem was already causing cancellations before 10 a.m. BST, and it was fixed by about 10:30 a.m.
“Early this morning (Monday 21 September) we experienced a technical issue at our Prestwick centre in Scotland. To maintain safety, air traffic regulations were applied to manage traffic demand while our engineers investigated.”
NATS continued;
“The issue has now been fixed and we are working closely with airports and airlines to safely remove the remaining air traffic restrictions as quickly as possible to minimise any further disruption.”
Citing a “connectivity issue” as the reason for the outage, NATS further said:
“It is nothing to do with the problem we had earlier this month.”
Airlines are demanding change
On Sept. 8, a software defect affecting the system for air space management caused flight chaos, cancelling two thousand flights with hundreds of thousands of passengers affected, with Gatwick, Manchester, Heathrow and Birmingham among the most affected.
In 2023, 700,000 passengers had their journeys disrupted by a computer shutdown and in 2025, another shutdown caused 150 cancellations.
Now, Ryanair has again called for NATS chief executive Martin Rolfe to resign, saying more than 140 of its flights have been delayed. EasyJet said the disruption calls into question the resilience of NATS’ systems and that it will do all it can to minimise the impact on passengers, while British Airways said some customers were likely to be affected by what it called yet another technical fault at NATS.
Jet2’s chief executive has said it is
“Simply not good enough”
and the airline will be counting the cost of the delays and asking NATS to compensate.
Although the issue is now resolved, the disruption is expected to continue throughout the day and aviation analytics company Cirium has said that 35 flights have been cancelled or did not fly so far. Some airlines are seeing delays of up to four hours.
Transport secretary Heidi Alexander said in a post on X:
“I know this will be deeply frustrating for passengers after the previous issue. There may be some delays as things reset. Please check with your airline for updates.”
NATS has also issued an apology and thanked passengers for their patience. It advised passengers to check with their airline in about the status of their flights.
Have you been affected by the chaos? Let us know in the comments below.
