Germany's Ryanair pilots will join a wave of strikes against the no-frills carrier across Europe on Friday, escalating a row over pay and conditions at the height of the summer season.
Ryanair proposed that a third-party mediator join talks with a trade union representing its Irish pilots who went on strike for a fourth time on Friday before wider stoppages planned around Europe next week.
Ryanair has suffered strikes in some of its other main markets such as Spain and Portugal as it struggles to reach collective labour agreements across Europe.
Faced with the prospect of widening strikes by crews in Europe, Ryanair Chief Executive Michael O'Leary on Tuesday threatened to move more jobs to Poland if walk-outs hurt its business.
Ryanair management had met with the Vereinigung Cockpit (VC) pilot union in Frankfurt last week. VC said the talks ended without the progress they had hoped for.
The airline says the cancellations have affected some 100,000 passengers who have either been put on alternative flights, or applied for full refunds.
The Irish airline said in a statement it expected disruption to the travel plans of almost 50,000 customers.
Flight FR7312 from Dublin to Zadar in Croatia lost cabin pressure and was diverted to Frankfurt Hahn airport.
Ryanair cabin crew in Spain, Portugal, Italy and Belgium are planning coordinated strikes and will announce dates for the action on Thursday, an official with Spanish union SITCPLA said.
Ryanair has agreed to buy a majority stake in the new Austrian leisure airline founded by former motor racing champion Niki Lauda in a major push on the German and Austrian markets dominated by Lufthansa.