Holidaymakers should brace for even more travel chaos in the coming days as airlines have been given a green light to cancel flights this summer without incurring in any fines.
Airlines are expected to announce a fresh wave of cancellations over the summer period as the government introduced an "airline slot amnesty".
Under this plan, airlines will be able to cancel flights without being penalised for not using their airport slot, but must finalise their summer schedule by Friday 8 July.
If a flight is planned later this summer and airlines feel they will not be able to staff it, they can cancel it without incurring fines or penalties.
Heathrow is expected to be affected the most by the cancellations as London's busiest airport struggles to cope with demand.
On Thursday and Friday, passengers at the airport complained of long queues, cancelled flights and lost baggage as “schedule intervention” and disruptions at UK airports were exacerbated by strikes in Spain.
The airport previously planned to carry 1.8 million passengers across more than 9,000 flights from Heathrow during July alone.
A Heathrow spokesperson said: "We encourage airlines to take this opportunity to reconsider their summer schedules without penalty and inform passengers as early as possible of any changes."
British Airways, whose services from Heathrow Airport are likely to bear the brunt of this week's cancellations, said the measures would help provide "certainty" to customers.
“We welcome these new measures, which help us to provide the certainty our customers deserve by making it easier to consolidate some of our quieter daily flights to multi-frequency destinations well in advance, and to protect more of our holiday flights," a spokesperson for British Airways said.
It is unclear how many flights British Airways will cancel but in a move set to affect more than 100,000 passengers, it announced last Friday it had axed a further 650 flights from London to destinations throughout Europe that were set to depart next month.
The routes most affected will include flights traveling to the popular Dutch capital Amsterdam and Greek capital Athens, as well as Barcelona, Malaga and Palma in Spain, and Faro in Portugal.
Gatwick said it would be reducing the number of flights during summer because of staff shortages even before the airport slot amnesty was first set out by the government on 21 June.
EasyJet (EZJ.L) said about 24 flights a day from Gatwick would be cancelled between Saturday 28 May and Monday 6 June.
Meanwhile, passengers face the prospect of disruption from strikes involving airline staff over the summer.
Staff at Ryanair (RYA.IR) and EasyJet have confirmed that they will stage industrial action in July following pay disputes. British Airways workers at Heathrow have also voted to strike, after the carrier did not repeal a 10% pay cut that was put in place over the pandemic.
Slots are used to manage capacity at the busiest airports, giving airlines authorisation to take off or land at a particular airport at a specified time on a specified day.
Airlines must use slots a certain amount of times each season in order to keep them, and this “amnesty” is giving them the leeway to put a more manageable schedule in place without the risk of losing a slot due to cancelled flights.
Rory Boland, editor of Which? Travel, said: “An amnesty on slot rules is potentially good news for passengers as it should encourage airlines who need to cancel more flights to do so now rather than at the last minute and could ease disruption this summer by letting better-staffed airlines step in and fly routes.
“For this to work, carriers must surrender their slots to other airlines if they are unable to fulfil them. This will help reduce cancellations and end the unsustainable practice of airlines flying near-empty planes to retain slots.”
Holidaymakers have already been hit by months of cancellations, delays and missing baggage.