A connectivity failure at National Air Traffic Services' Prestwick centre delayed flights across Scotland and Northern England on September 21, 2026 — the second NATS technical failure in a month, following an earlier software fault that forced more than 2,000 flight cancellations.

NATS said air traffic regulations were applied to manage demand while engineers investigated, a standard flow-control measure that translates directly into departure delays at affected airports.

Liverpool John Lennon (LPL), Manchester (MAN), Belfast International (BFS), Edinburgh (EDI) and Glasgow Prestwick (GLA) all reported disruption to operations. Flights bound for affected airports from unaffected fields also faced possible delays. NATS stressed that airports south of Manchester were "broadly unaffected," though flights heading north and departures from Scottish airports were subject to delay.

"Our engineers are continuing to investigate the issue at our Prestwick centre in Scotland. Airports south of Manchester are broadly unaffected, however flights heading north and flights departing Scottish airports are now subject to some delay," NATS said. "Passengers should check with their airlines. This is unrelated to the issue two weeks ago. We apologise for the disruption."

British Airways, easyJet and Ryanair passengers all faced delays and disruptions. Ryanair issued a statement confirming the scope: "We have been advised of a NATS Air Traffic Control equipment failure today affecting the airspace above Scotland/Northern England. As a result, we expect some delays to flights to/from the UK and Ireland."

At around 10:30 local time, UK Secretary of State for Transport Heidi Alexander announced the resolution. "Engineers have fixed the problem and systems are resuming," she said, while cautioning that delays would persist: "I know this will be deeply frustrating for passengers after the previous issue. There may be some delays as things reset."

NATS later confirmed the fault was repaired and explained its cause. "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," the operator said. "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."

The company characterized the fault as narrow in scope. "This was a connectivity issue with part of our systems network, specific to the operation in Scotland. It is nothing to do with the problem we had earlier this month," NATS said, before apologizing to passengers and advising them to continue checking with airlines.

The outage lands at a difficult moment for NATS. The earlier software failure this month cancelled more than 2,000 flights across the UK, and Alexander's reference to passenger frustration underscores the political pressure now attached to the air navigation provider's reliability record. Two unrelated system failures within weeks raise questions about infrastructure resilience at Prestwick, which controls airspace over Scotland and Northern England.

With restrictions being lifted progressively, carriers should recover schedules through the day, though knock-on delays and aircraft rotations may extend disruption into subsequent flights.