Gatwick Airport is limiting its number of flights this week due to an exceptional shortage of air-traffic controllers, caused partly by Covid infections.
The airport this week imposed a daily 800-flight limit from Monday until Sunday affecting departures and arrivals.
The decision has led to the cancellation of 29 flights on Wednesday, 40 on Thursday, 65 on Friday and 30 next Monday, the London airport said.
Tuesday and Saturday are not scheduled to be affected by the restrictions, which were imposed because 30 per cent of the airport's National Air Traffic Service (Nats) control tower staff are unavailable for a variety of medical reasons, including Covid-19.
A spokeswoman for Gatwick told The National the plan was for flights to be cancelled proportionately between airlines.
But Ryanair said it will not be cancelling any flights and called on the Civil Aviation Authority (CAA) to "immediately intervene" and protect passengers from further disruptions.
The budget airline said in a statement: "Ryanair pays Nats almost €100 million per annum for an ATC service that is repeatedly short staffed and which, on 28th August, collapsed completely causing the cancellation of over 2,000 flights (over 360,000 passengers) and long delays to more than 5,000 flights (900,000 passengers).
"This shambles has been followed with more flight disruptions at Gatwick Airport on six separate occasions over the past four weeks and now Gatwick Airport is imposing a daily cap of 800 flights until Monday 2 Oct and asking airlines to cancel flights, which Ryanair will not be doing."
London Gatwick chief executive Stewart Wingate called the cap “a difficult decision” but said the limit was needed to create “reliable flight programmes” amid continuing work with Nats to “build resilience in the control tower”.
Passengers took to social media overnight to complain, with one saying they had suffered a delay after landing due to “Gatwick staff not opening doors”.
Others said their flights had been affected by repeated delays.
“Going out to Tenerife – four-hour delay and then plane cancelled while sitting on the plane, next day three-hour delay! Way back sat on the run away for two hours then took off then finally off plane gone 2am! Not impressed @Gatwick_Airport,” wrote the passenger.
“This has been a difficult decision but the action we have taken today means our airlines can fly reliable flight programmes, which gives passengers more certainty that they will not face last-minute cancellations,” Mr Wingate said.
“We are working closely with Nats to build resilience in the control tower and this decision means we can prevent as much disruptions as possible.
“London Gatwick would like to apologise to any passengers who have been impacted by these restrictions.”
Gatwick Airport through the years – in pictures
Nats apologised to passengers but said a variety of medical reasons meant “we cannot manage the number of flights that were originally planned for this week”.
“We have worked very closely with Gatwick airport throughout,” it said in a statement. "Given the levels of sickness we have experienced over the last few weeks we believe it is the responsible thing to do to limit the number of flights this week in order to reduce the risk of daily disruption to passengers using the airport.
“Our operational resilience in the tower will improve as our staff return to work and we move out of the summer schedule, which is particularly busy at Gatwick.
“We continue to train additional air-traffic controllers and expect another group to qualify to work in the tower over the coming months, ready for next summer.
“Even an experienced air-traffic controller takes at least nine months to qualify at Gatwick and very few are able to do so, as Gatwick is such a busy and complex air-traffic environment.”
About 1,500 flights serving airports across the UK were cancelled, with many others delayed, on August 28, a bank holiday and one of the busiest travel days of the year.
An initial inquiry by Nats found the problem was caused by its system failing to process a flight plan correctly.
“While it is regrettable that a temporary limit on capacity at Gatwick Airport is required, we believe that it is the right action by the airport so on the day cancellations and delays can be avoided,” said Johan Lundgren, chief executive of easyJet.
“Gatwick Airport and Nats now need to work on a longer-term plan so the resilience of ATC [air-traffic control] at Gatwick is improved and fit for purpose.
“Our call for a more wide-ranging review of Nats remains so the broader issues can be examined so it can deliver robust services to passengers now and in the future.”
A spokesman for the easyJet, which apologised for any inconvenience that was outside of its control, said affected passengers would be contacted as soon as possible and may be able to rebook or get a refund.