Ryanair said on Wednesday it would cancel more than 12% of its flights on July 25 and 26 due to a cabin crew strike, as its industrial relations crisis escalates.
The Irish airline said in a statement it expected disruption to the travel plans of almost 50,000 customers travelling to and from Belgium, Portugal and Spain as it would cancel up to 300 flights per day.
Ryanair, Europe's largest low-cost carrier, cancelled 30 flights on July 12 when some pilots in Ireland staged the company's largest strike to date.
The planned strikes, which are aimed at achieving improved working conditions, deal another blow to the Irish airline’s attempts to quell a staff revolt that began last year.
Cabin crew from across Europe published a list of 34 demands on July 4, including "a fair living wage", improved sick pay and employment contracts in their own language based on local rather than Irish law.
Ryanair says its staff have some of the best conditions in the low-cost airline industry.
Cabin crew say the carrier has failed to improve conditions sufficiently after recognising unions in December.
Ryanair, which flies in 37 countries and carried 130 million passengers last year, averted widespread strikes before Christmas by deciding to recognise trade unions for the first time in its 32-year history. But it has since struggled to reach agreement on terms with several of them.