Ryanair's confirmed it will cancel 24 flights this Friday during a strike by Dublin-based pilots.
The airline will text or email affected passengers to arrange a refund or alternative flight.
It's the second action by Ryanair pilots in a row with the airline over working conditions - a third strike day is planned for the 24th of July.
In a statement Ryanair says the strike is unnecessary, and the "Forsa union and the pilots committee don't even understand that their demands will damage Irish pilots prospects."
In a statement this afternoon, the airline said the cancellations affect "high frequency routes" between the UK and Ireland "to minimise the impact on the holiday plans of Irish families travelling to the continent.
Pilots are calling for the introduction of a transparent seniority system, which could be used as the basis for decisions on base transfers, promotion, leave allocation and other issues.