Ryanair's pilots in the Republic of Ireland have voted to go on strike for 24 hours from 0100 on 12 July, with knock-on effects expected across the airline's network.
They have warned that if their demands are not met, Ryanair risks a summer of industrial action - but have no plans at present to ballot members for strike action in the 21 countries where they operate.
Europe's largest low-priced airline, Ryanair is coming under mounting pressure to improve cabin crew working conditions after a coalition of unions led by the International Transport Workers Federations (ITF) published a list of 34 demands it wants Ryanair to meet.More news: Ryanair warns of cancelled flights on Thursday after pilot strike vote
The 24 hour strike is planned for 12 July, the start of traditional holidays in Northern Ireland.
"Conditions at Ryanair have been heavily criticised over the last few years, with the range of issues highlighted including poverty pay, draconian disciplinary procedures, unachievable sales targets sand staff having to pay for items that most decent employers provide".
The union said it remained available and willing to engage on the issues identified in the notice of strike action.
"Our member pilots directly employed by Ryanair complain that there is no transparent system for the determination of important matters including voluntary and involuntary base transfer, command upgrade, allocation of annual leave and promotion", it said.More news: Congress to Trump: Cancel Putin summit after new Mueller indictments
Cabin crew from across Europe could follow suit at some stage. Ryanair said the cancellations compare with just 41 in June past year.
She said any compensation depends on when passengers are notified of a cancellation or delay and that most of the time airlines offer a re-route or a flight at a later day depending on seat availability.
The airline has now grown so large that it was recently officially recognised as Europe's largest airline in terms of passenger numbers - carrying 1.5 times as many passengers as arch-rival easyJet and double the number of passengers as Lufthansa.
"What Ryanair pilots are asking for is commonplace in many airlines and is not unreasonable".More news: Jabari Parker, Chicago Bulls are progressing on a deal