The airline said on Wednesday it will cut its Irish fleet by a fifth to 24 aircraft for winter 2018, blaming pilot walkouts for hurting bookings, air fares and consumer confidence in Irish flight schedules. It said it has sent letters informing more than 100 pilots and 200 cabin crew that their services may not be needed from October 28.

The announcement comes as cabin crew in Spain, Belgium, Portugal and Italy hold one or two-day walkouts starting Wednesday in disputes over pay and conditions. The airline has cancelled 600 flights in response to the strikes, following similar action by Irish pilots on Tuesday that also led to flight disruptions. The conflict is starting to weigh on earnings, with the company posting a 20% drop in first-quarter profit on Monday.

Ryanair’s shares rose as much as 2.9% after the Dublin fleet cut, a sign that investors stand behind Chief Executive Officer Michael O’Leary’s attempt to undercut the union-led action. The discount giant has said it won’t concede to “unreasonable demands.”

The disruptions at the height of Europe’s busiest summer travel season mark the first major industrial action the budget carrier has seen after it agreed to accept unionisation in the face of a staffing crunch last year.

Germany’s Vereinigung Cockpit pilot union is also holding a vote on possible strike action, with the outcome due later this month.