Flight delays and cancellations continued on Wednesday as the UK grappled with the aftermath of a technical glitch at National Air Traffic Services (NATS), the country’s air traffic control provider. According to tracking website FlightRadar24, at least 177 flights were cancelled on Wednesday, adding to more than 1,300 cancellations the previous day. The disruption has affected tens of thousands of passengers, with major airports such as Heathrow, Gatwick, Manchester, and Birmingham reporting significant delays and cancellations.

NATS CEO Martin Rolfe apologised for the disruption, stating that a full investigation into the issue was underway. He also confirmed that the problem was in the company’s flight data processing system, which is different from the one that failed during a 2023 incident. Rolfe said the issue had been resolved, but the backlog of flights is expected to cause further delays. Transport Secretary Heidi Alexander has summoned Rolfe to a meeting to address the disruption and the government’s response, with Alexander also confirming that a cyber attack was not the cause of the fault.

The disruption has had a cascading effect on the aviation network, with some flights unable to depart overseas airports due to restricted landing space. At Heathrow, one of the busiest airports in Europe, departures were initially paused around lunchtime, then resumed before facing further disruption in the afternoon. Thirteen Heathrow-bound flights were diverted to other UK and European airports. British Airways and EasyJet reported hundreds of cancellations, with Ryanair stating that over 65,000 passengers had been delayed by up to eight hours.

Passengers have been advised to contact their airlines for updates, with some reporting long waits on the tarmac. Phil White, a passenger at Gatwick, described being left waiting for hours with no clear information. Chloe Davis, a 18-year-old passenger at Heathrow, said she was waiting on a Virgin plane for her flight to Orlando, with no gates available for incoming aircraft. Airlines have urged passengers not to travel to airports due to busy call centres.

Airlines and aviation analysts have called for reforms to NATS, with Ryanair and Wizz Air previously urging an overhaul of the organisation. Ryanair’s Chief Operations Officer Neal McMahon accused NATS of failing to deliver on promises to fix the system, despite assurances. Aviation analyst John Strickland warned that even a short outage can have severe consequences due to the tightly scheduled nature of airline operations. The UK Civil Aviation Authority has stated it will expect NATS to provide a full report on the system failure and consider whether reforms are needed to ensure the reliability of the air traffic control system.

The situation remains unresolved, with the backlog of flights expected to cause further delays. Passengers are advised to continue checking with their airlines for the latest updates as the aviation network works to recover from the disruption.