EasyJet has cancelled 1,700 summer flights, primarily from London Gatwick, potentially disrupting the holiday plans of thousands of passengers. After a number of short-notice cancellations at the Sussex airport in recent days, the move will prompt fresh concern about the resilience of squeezed European airspace to deal with booming demand, with more air traffic control strikes threatened. The airline said 95% of those affected had already been contacted and rebooked on alternative flights, and the remaining passengers would be notified and offered refunds or rebooking on Monday. It is understood about 9,000 passengers have yet to be put on new flights. It said most of the cancellations were those with multiple departures and would amount to less than 2% of its remaining schedule for July and August. It blamed “unprecedented air traffic control delays” and said these “pre-emptive adjustments” were not a sign of the same kind of problems with ground staffing that forced easyJet and other airlines to cancel thousands of flights last year. Dozens of easyJet flights were axed over the weekend to and from Gatwick, where it is by some distance the biggest carrier. The cancellations could drive peak summer fares even higher, with capacity still roughly 10% below 2019 levels, although more flights will depart the UK this month – 92,400, with 16.5m seats – than any month since October 2019, according to data from analysts Cirium. Airspace remains a worry for UK airlines, with frequent French air traffic control strikes in particular forcing carriers to divert to longer paths. Eurocontrol, which manages and coordinates airspace around Europe, has warned of “challenging conditions”, with the war in Ukraine constraining available flight paths, as well as more possible summer strike action. An easyJet spokesperson apologised to customers for any inconvenience, and said: “We are currently operating up to around 1,800 flights and carrying around 250,000 customers per day with more crew and pilots flying than ever before, and like all airlines we review our flights on an ongoing basis. “As Eurocontrol has stated, the whole industry is seeing challenging conditions this summer with more constrained airspace due to the war in Ukraine resulting in unprecedented ATC delays, as well as further potential ATC strike action. “We have therefore made some pre-emptive adjustments to our programme consolidating a small number of flights at Gatwick, where we have multiple daily frequencies, in order to help mitigate these external challenges on the day of travel for our customers, and we continue to operate around over 90,000 flights over this period.” Gatwick, easyJet’s biggest base and also one of the busiest single-runway airports in the world, is approaching capacity again. Last week it identified air traffic control issues as its major concern for summer, as it submitted planning permission for a second runway. “These cancellations will be incredibly disappointing for thousands of travellers whose summer holiday plans could be in jeopardy,” said Rocio Concha, Director of Policy and Advocacy at the consumer group Which? “EasyJet must ensure it is doing everything it can to assist passengers impacted by this decision and ensure they can easily access help to be rerouted or refunded at the earliest available opportunity".”