The underlying issue causing Monday’s disruption has since been resolved, with Nats saying it was running at “full capacity” although officials warned of knock-on effects.
A spokesperson said they were now “focused on working with our customers to recover their residual delays and help get their operations back to normal”.
Easyjet was the worst affected airline, with 47 of its 670 scheduled departures cancelled, while British Airways has seen 12 cancellations from its 513 scheduled departures.
The UK Civil Aviation Authority (CAA) said passengers who had flights disrupted were “unlikely” to be entitled to compensation.
It said the technical issue is “likely to be considered the result of ‘extraordinary circumstances’ under passenger rights rules”, meaning that “although passengers should be looked after by airlines, they are unlikely to be entitled to compensation for delays or cancellations that were directly caused by the incident”.
An independent review by the CAA into the resilience of the UK’s air traffic control system is under way and the results will be published “within six months”, it said.
Industry representative body Airlines UK said both passengers and airlines “deserve better” service after “yet another Nats failure”.
Managing director of Wizz Air UK, Yvonne Moynihan, called for “urgent reform” of Nats, adding that she did not have confidence in its current leadership.
Asked on BBC Radio 4’s World at One programme if Nats chief Martin Rolfe should resign, Moynihan said: “We need to look at the leadership at the top. But more than that, what are the board of directors doing?”
Jet2 boss Steve Heapy called for “urgent and accountable” action to bolster the UK’s air traffic control infrastructure.
Ryanair reiterated its calls for Rolfe to resign, saying he had failed to deliver” either a reliable system or an effective back-up”. The latest outage affected 140 of the airline’s flights and 25,000 passengers.
British Airways said “yet another technical fault with Nats” was “disappointing”.
