National Air Traffic Services (Nats) has warned that UK flights will still face delays despite a technical issue at its air traffic control systems being fixed within a few hours.

The technical issue caused Nats to impose immediate limitations on the number of incoming flights, leading to stranded travellers within the UK and abroad. Thousands of air passengers faced delays and cancellations as Nats reported a technical issue that affected its air traffic control systems Monday morning.

Heathrow Airport, one of the busiest international airports in the world, bore the brunt of the disruption.

By late Monday, departure and arrival boards remained dominated by delay notices, with no clear timeline for a return to normal operations. Travellers scheduled to fly on Tuesday were advised to contact their respective airlines for the latest updates before making their way to the airport.

Gatwick Airport, another major hub in the UK, assured passengers of a regular schedule for Tuesday. However, the airport management strongly recommended that travellers verify their flight status with their airlines beforehand.

London Luton Airport cautioned passengers that flight operations within UK airspace were still susceptible to delays and cancellations. The airport urged individuals to stay updated on their flight’s status through direct communication with their respective airlines.

British Airways recommended that those with short-haul flights verify their flights’ operational status before heading to the airport. Passengers scheduled to travel on Monday and Tuesday were informed that they might have the option to reschedule their flights without incurring additional charges.

Ryanair reported that it had to either delay or cancel certain flights. Jet2 extended advice to passengers scheduled to travel on Tuesday. The airline recommended that they stick to their original plans of heading to the airport unless specific advice to the contrary was issued.

Aviation analyst Sally Gethin predicted that the repercussions of the technical issue were far from over. Gethin highlighted that airlines now face the daunting task of managing customer concerns while striving to restore flight schedules to a more regular state.

She suggested that notable disruptions might continue over the upcoming hours and into the following day.

Aviation data firm Cirium shed light on the scale of the flight disruptions caused by the technical issue. On Monday, a total of 3,049 departures were initially scheduled from UK airports, along with an additional 3,054 expected arrivals. By 14:30 BST, Cirium’s data indicated that approximately 8% of departures and 9% of arrivals had been cancelled due to the issue.

Transport Secretary Mark Harper advised passengers to stay informed by reaching out to their airlines and acquainting themselves with the guidance provided by the UK Civil Aviation Authority (CAA). This guidance outlines passenger rights in situations of flight delays or cancellations.

The CAA stipulates that airlines are obligated to provide food, beverages, and accommodations if delays extend overnight. In cases of flight cancellations, passengers must be offered a choice between a refund or alternative travel arrangements at the earliest convenience.

Apologising for the widespread inconvenience caused, Nats’ Operations Director Juliet Kennedy announced an ongoing investigation into the root cause of the incident.

Aviation strategy consultant Graham Lake described the event as a rare and serious system failure that necessitated a transition to a manual system with limited capacity. Lake highlighted that such technical faults are extremely uncommon in the aviation industry, with the most recent incident of this nature occurring back in 2014.