Pilots at Ryanair are to be balloted on whether to take industrial action in a dispute over pay and conditions.
Members of the British Airline Pilots Association (Balpa) will vote in the coming weeks, with the result due next month.
The union said there were a number of areas of concern for pilots on issues such as pensions, maternity benefits, allowances and a "fair, transparent and consistent" pay structure.
Balpa general secretary Brian Strutton said: "Our Ryanair representatives have been trying to tackle some of the many issues that result from years of non-recognition of unions within Ryanair.
"But we have not been able to make any progress with Ryanair at all on any of our areas of concern."