Ryanair is cancelling up to 50 flights a day over the next six weeks to catch up with staff holiday entitlement.
The decision enraged passengers who turned to Twitter to voice their anger at the cancellations and lack of notice or explanation.
Customers described the cancellations as an “absolute disgrace” and “shocking”.
According to Ryanair the cancellations represented two per cent of the airlines schedule.
“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,” the airline’s head of communications, Robin Kiely, said in a statement.
He explained: “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 capacity delays and strikes (in France), has severely reduced our on-time performance over the past two weeks to under 80 percent.
“By cancelling less than two percent 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 percent.”