Over 200 UK flights cancelled after second air traffic glitch

More than 200 flights across the United Kingdom were cancelled on Monday, 21 September, after a fresh air traffic control fault in Scotland triggered the second major disruption to UK aviation in less than a fortnight.

New technical problem hits Prestwick control centre

Publicly available information indicates that the latest disruption originated at National Air Traffic Services’ (NATS) control centre at Prestwick in Ayrshire, which manages traffic across large parts of Scotland, Northern Ireland and northern England. The company reported a “technical issue” with systems handling airspace in the north of the UK shortly after 09:30 BST on Monday.

NATS stated that the problem affected the ability to safely manage traffic in the affected sectors, prompting capacity restrictions while engineers worked to restore normal operations. By mid-afternoon, UK transport officials reported that the issue had been resolved and that systems were resuming, although residual disruption was expected to continue into the evening as schedules recovered.

Aviation data from Cirium, cited in multiple news reports, showed at least 200 flights cancelled by early afternoon, with some tallies rising to around 227 cancellations by late in the day. The impact was concentrated at airports with a high volume of services to and from Scotland and Northern Ireland, but knock-on delays were reported more widely across the network.

Unlike the earlier incident this month, which was traced to a software defect in NATS’ flight-planning system, the organisation has described the Prestwick problem as a separate connectivity or communications fault. Detailed technical findings have not yet been fully published, and officials have said that investigations are continuing.

Airports across the UK feel the impact

Airports in Scotland experienced some of the most visible disruption. Glasgow, Edinburgh and Aberdeen all reported cancelled departures and arrivals, with queues forming at check-in and customer service desks throughout Monday. Passengers bound for destinations across Europe described learning of cancellations only on arrival at the terminal, as airlines worked through rapidly changing operational plans.

UK-wide data suggests that disruption extended beyond Scotland. Services linking northern England to London and European hubs were among those affected, with delays and cancellations reported at Manchester, Newcastle and Leeds Bradford. Some domestic services operated with long delays as airspace capacity was gradually restored, while others were removed from schedules entirely to help airlines reset networks.

Major carriers including easyJet, Ryanair and British Airways all cancelled flights. According to figures referenced in industry reporting, easyJet saw several dozen departures removed from its Monday schedule, while other European and UK operators experienced smaller but still significant cuts. Regional airlines serving the Highlands and Islands also reported delays as they adjusted to the restricted flow of traffic through affected sectors.

Timetables began to stabilise overnight into Tuesday, 22 September, but airlines continued to warn of residual disruption, particularly for aircraft and crew that ended the day out of position. Travellers with early-morning departures were advised to monitor their flight status closely and allow extra time at airports in case of schedule changes.

Second major disruption in two weeks raises pressure on NATS

The Prestwick failure has intensified scrutiny of NATS because it comes less than two weeks after a separate and more extensive air traffic control incident on 8 September. In that earlier case, a defect in flight data processing software forced controllers across the UK to enter flight plans manually, triggering the cancellation of more than 2,000 flights over two days and affecting hundreds of thousands of passengers.

An initial report on the 8 September event described the defect as a previously unknown software issue triggered by a specific, rare sequence of flight plan data. NATS emphasised that it had identified and rectified the flaw, and pledged to improve resilience and testing of critical systems. The Prestwick connectivity fault, however, has raised renewed questions about whether wider aspects of the UK’s air traffic infrastructure and contingency arrangements are robust enough.

Airlines and industry bodies have issued strong public criticism following the latest disruption. Carriers have argued that repeated technical problems in a short period threaten confidence in the reliability of UK airspace management and impose heavy financial and operational costs on operators. Several airline executives have called for an independent review of NATS’ technology, staffing and back-up systems, alongside clarity on compensation and cost-sharing arrangements for major outages.

The UK government has acknowledged the severity of the disruption and requested regular updates from NATS on both the Prestwick fault and the implementation of recommendations arising from the earlier September outage. Publicly available statements from ministers have stressed that safety remains the overriding priority, but that reliability and resilience must also meet the expectations of passengers and industry.

What affected passengers can expect under UK and EU rules

The second major disruption in a matter of weeks has again highlighted the complex rules governing passenger rights when flights are cancelled or heavily delayed by air traffic control failures. Under retained EU Regulation 261/2004, which continues to apply in the UK, airlines must offer affected passengers a choice between a refund of the unused ticket, re-routing at the earliest opportunity, or re-routing at a later date chosen by the passenger, subject to seat availability.

Where flights are cancelled at short notice or delayed by more than several hours, airlines must also provide care and assistance, which can include meals, refreshments, hotel accommodation where an overnight stay becomes necessary, and transport between the airport and accommodation. Guidance from the UK Civil Aviation Authority emphasises that these obligations apply even when the cause of disruption lies with third parties such as air traffic control providers.

However, compensation payments for inconvenience and lost time are treated differently. Air traffic control failures are generally categorised as extraordinary circumstances beyond an airline’s control. In such cases, while carriers must still provide refunds or re-routing and care, they are typically not required to pay additional cash compensation that would otherwise be due for cancellations or long delays caused by technical faults within the airline itself.

Consumer advocates advise passengers to keep all receipts for reasonable expenses incurred during disruption, including food, accommodation and local transport, and to submit claims promptly through airline customer service channels. Travellers who booked package holidays may also have additional protections through tour operators, while those using comprehensive travel insurance can seek reimbursement for some out-of-pocket costs not covered by airlines.

Ongoing questions over infrastructure resilience

For frequent travellers and the wider tourism industry, the rapid succession of incidents has raised broader concerns about the resilience of critical aviation infrastructure. NATS handles around 2.5 million flights per year in UK airspace, and the system had operated for long periods without major disruption before the August 2023 outage, the 8 September 2026 software defect and now the Prestwick connectivity fault.

Aviation analysts note that while no safety incidents have been linked to the recent failures, the operational and economic impacts are substantial. Airlines face lost revenue and complex recovery operations, airports must manage sudden surges of stranded passengers, and tourism businesses from hotels to attractions see bookings affected when travellers are delayed or forced to abandon trips.

Industry commentary suggests that forthcoming technical investigations will focus on three main questions: whether the systems architecture at NATS has sufficient redundancy, whether software and communications updates are being tested rigorously enough before deployment, and how quickly contingency procedures can restore a meaningful level of capacity when faults occur. Comparisons are being drawn with other major European air navigation service providers that have also experienced outages but may have recovered more rapidly.

For now, travellers planning to fly to, from or within the UK in the coming days are being urged to pay close attention to airline alerts and airport departure boards. While schedules are expected to return to normal once the system stabilises, recent events indicate that disruption from air traffic control issues can develop quickly and have far-reaching effects across the network.