Ryanair has announced it will cancel between 40 and 50 flights a day for the next six weeks due to a backlog of staff annual leave.
The budget airline says the measure is designed to improve punctuality, which has fallen below 80% in the first two weeks of September.
Some customers have reacted furiously to the cancellations, claiming holiday plans have been ruined by the decision.
The airline is changing its internal calendar as part of increases in holiday allowances for pilots and cabin staff, which has contributed to the backlog.
A Ryanair spokesperson said: “We have operated a record schedule (and traffic numbers) during the peak summer months of July and August but must now allocate annual leave to pilots and cabin crew in September and October (while still running the bulk of our summer schedule).
“This increased leave at a time of ATC [air traffic control] capacity delays and strikes has severely reduced our on-time performance over the past two weeks to under 80%. By cancelling less than 2% of our flying programme over the next six weeks, (until our winter schedule starts in early November) we can improve the operational resilience of our schedules and restore punctuality to our annualised target of 90%.
“We apologise sincerely to the small number of customers affected by these cancellations, and will be doing our utmost to arrange alternative flights and/or full refunds for them.”
If the airline cancelled 40 flights per day for six weeks at a load factor of 90%, approximately 285,000 journeys would be affected.
Europe’s largest airline by passenger numbers sent emails to the first affected passengers on Friday, giving them the choice of a refund or an alternative flight.
The airline said it would waive the usual €40 (£35) surcharge for changing flights. However, a Reuters reporter, whose flight from Dublin to Barcelona tomorrow was cancelled on Friday, was offered a choice of a surcharge of €250 to take an earlier flight on the 18th or €60 to take a flight on 19th September.