In another setback for Ryanair, its pilots in Ireland voted on Friday to strike unless they're given a pay rise.
The budget airline's pilots in Spain are also threatening to strike — they're expected to hold a vote in the next few days.
Last week UK-based pilots agreed to go on strike for two days in August and two more in September.
Ryanair, which is Europe's biggest budget airline, was hit by waves of strikes by pilots and cabin crew last year.
They led to the cancellation of hundreds of flights as well as the airline agreeing to recognise trade unions for the first time.
Ryanair managed to quell the disputes by reaching deals with many unions in Europe on pay and allowances, but it has yet to move beyond recognition agreements with others and further angered unions by telling staff 10 days ago that had 900 pilots and crew more than it required.