Ryanair announced today that it has cancelled 20 flights scheduled for next Friday, August 3.
The cancellations come as Irish Ryanair pilots are set to hold a fourth day of strikes.
Ryanair says the affected flights, which are on Ireland-UK routes, account for just 7% of the 300 flights planned to go to and from Ireland next Friday.
The airline said in a statement that the cancellations were "regrettable" but that all 3,500 affected customers have been notified and will be re-accommodated or refunded.
Around 100 Dublin-based Ryanair pilots announced their intention to hold one-day strike yesterday.
Meanwhile, the airline warned that the jobs of up to 300 pilots and cabin crew could be at risk, as it plans to scale back its fleet in Dublin.