Ryanair Holdings Plc staff in Italy announced plans to strike on June 25, adding to Europe’s travel headaches as the industry tries to recover from the coronavirus pandemic.

Unions representing pilots and flight attendants will strike for 24 hours to press demands for better working conditions, they said on Thursday. The walkout will also involve staff in Spain, Portugal, France and Belgium, they said.

Tourists are facing delays and cancellations across the continent as strikes and labor shortages strain European airports amid the long-awaited post-lockdown travel boom.

A technical malfunction in Switzerland, which disrupted air traffic control systems on Wednesday, was the latest disruption.

Ryanair’s labor organizations in Spain, Belgium, France, Italy and Portugal have been coordinating to organize continent-wide protests if Europe’s largest low-cost carrier refuses to negotiate.