Ryanair flights delayed after NATS Prestwick control centre suffers second fault in two weeks

Quick summary

National Air Traffic Services suffered a second technical failure in under two weeks when a connectivity fault at its Prestwick control centre in Scotland disrupted UK flights on 21 September 2026. The outage cancelled 72 flights out of more than 6,000 scheduled UK movements and delayed more than 140 Ryanair services, affecting roughly 25,000 passengers. Glasgow and Belfast bore the heaviest disruption; London-area airports were largely unaffected.

NATS confirmed the fault was unrelated to the software defect that cancelled more than 2,000 flights on 8–9 September. That distinction matters less to passengers than the pattern it reveals.

Two failures in thirteen days. That is the record NATS is now defending as it faces renewed calls for its chief executive to resign and a government-commissioned review of whether the UK’s air traffic control system is adequately funded and structured to handle the traffic it carries.

The 21 September fault was a connectivity problem inside the part of NATS’s systems network serving Scottish operations. Engineers imposed regional flow restrictions across northern UK airspace while they diagnosed the issue, restoring normal service later that morning. NATS apologised and said it was working with airports and airlines to limit further disruption — the same language it used a fortnight earlier, after a far more damaging software defect grounded flights across the entire country.

This time the numbers were smaller. Aviation analytics firm Cirium put the early-day cancellation rate at roughly 1% — close to what a normal full day looks like — though it cautioned the total would likely grow as the day progressed. The earlier September outage, by comparison, produced more than 2,000 cancellations and disrupted over 330,000 passengers.

Smaller does not mean inconsequential. For the 25,000 Ryanair passengers caught in delays, or anyone whose Glasgow or Belfast connection fed into a long-haul itinerary, the morning was a scramble. UK transport minister Heidi Alexander called it deeply frustrating for passengers given how recently the previous disruption had occurred.

What the Prestwick fault actually was — and why it matters that it’s different

NATS was explicit: the Prestwick connectivity problem and the 8–9 September software defect are not the same fault. The earlier failure originated in a specific section of NATS’s flight data system code, according to a preliminary investigation whose findings were reported by Reuters. That defect required nationwide capacity reductions and manual handling procedures across UK airspace. The 21 September event was a network link failure confined to Scottish operations — controllers imposed regional restrictions while engineers restored connectivity, and traffic south of Manchester largely continued without interruption.

Different failure modes. That is the uncomfortable part.

It means NATS is not dealing with a single recurring bug it can patch and move on from. The incidents point to vulnerabilities in both core software and peripheral network infrastructure — two separate layers of a system that handles some of the world’s busiest airspace. Aerotime reported the technical detail of the Prestwick fault, confirming NATS applied flow restrictions in northern UK airspace before restoring normal service the same morning.

Following the earlier September outage, the UK government tasked the Civil Aviation Authority to conduct an independent review — not just of what went wrong technically, but of whether NATS is adequately configured and funded to deliver a resilient service. Airways Magazine reported that the review includes scrutiny of NATS’s future investment plans and its regulatory accountability. A second failure within the review window will make that examination considerably harder to contain.

Ryanair, which reported the 140-plus delayed flights on 21 September, issued a corporate statement calling for NATS chief executive Martin Rolfe to resign or be removed by Transport Secretary Alexander. Downing Street had backed Rolfe after the first September incident. Whether that backing holds after a second failure is an open question the government has not yet answered publicly.

For travelers connecting through UK hubs toward Asia-Pacific, flights from Europe to Japan and other long-haul routes that transit UK airspace face the most exposure when NATS restricts capacity — a missed connection at Heathrow or Manchester can cascade into a 24-hour delay on the other side of the world.

Why compensation is harder to claim than passengers expect

Here is the part that catches travelers off guard. When an air traffic control failure causes your flight to be cancelled or delayed, the airline almost certainly does not owe you statutory cash compensation — and that applies whether the disruption lasts two hours or two days.

Under both UK261 and EU261/2004, ATC failures are classified as extraordinary circumstances: events outside the airline’s control that exempt carriers from the fixed compensation payments (up to £520 under UK rules) that apply to airline-caused disruption. The UK Civil Aviation Authority confirmed this position explicitly in guidance issued after the 8 September disruption, stating that the NATS technical problem would generally be treated as extraordinary circumstances.

What airlines must still provide — regardless of cause — is duty of care: meals and refreshments during a significant wait, hotel accommodation if an overnight stay becomes necessary, and rebooking on the next available service. The CAA is clear on this. The distinction between “no cash compensation” and “no obligation whatsoever” is one airlines sometimes blur, and passengers who accept a voucher without pressing for full care entitlements often leave money on the table.

Travel insurance is the other lever. Policies covering trip disruption or missed connections can pay out where statutory compensation does not — but only if you have kept receipts and documented the cause of disruption. A screenshot of the airline’s delay notification citing ATC restrictions is worth saving.

What to do if your UK connection is at risk

NATS has now failed twice in September 2026, and a CAA review of its resilience is underway — anyone transiting UK airspace in the coming weeks should treat schedule risk as elevated, not exceptional.

• Check live status before leaving for the airport. NATS publishes service status updates, and airline apps will flag disruption faster than airport departure boards. Glasgow and Belfast are the highest-risk airports right now; London Heathrow, Gatwick and Manchester have been less affected in both recent incidents.
• Build buffer into UK transfer itineraries. A 90-minute connection at Heathrow is tight on a normal day. During an ATC flow restriction, it is a missed flight. If your itinerary feeds into a long-haul departure — particularly Europe–Asia or transatlantic — consider whether a same-day alternative exists if the inbound is delayed.
• Know what you are owed, and ask for it explicitly. If your flight is cancelled or delayed by more than two hours, ask the airline for meals, accommodation if needed, and rebooking — in writing if possible. Do not accept a voucher as a substitute for hotel accommodation. Cash compensation under UK261 or EU261 is unlikely to apply given the ATC cause, but duty of care is not optional.
• Keep all receipts and document the cause. Screenshot the delay notification, note the ATC reference if the airline provides one, and retain food and hotel receipts. Your travel insurer will need this documentation to process a trip disruption claim.
• Check whether your credit card covers trip disruption. Some premium travel cards include missed connection or trip delay cover that activates when the cause is outside the airline’s control — exactly the scenario ATC failures create.

Watch: The CAA’s independent review of the 8 September outage is ongoing. If its findings extend to the 21 September Prestwick fault — or if the government widens the review’s scope — that will signal whether tighter resilience obligations are coming for NATS. A further incident before the review concludes would almost certainly accelerate that outcome.

Questions? Answers.