The Svensk Pilotförening (SFP) union said it had tried to start negotiations with Ryanair over the past eight months without success, and that at an April meeting the airline refused to accept the union delegation and wanted to choose the union's negotiation team.
The union said it was willing to explore the option of a third-party facilitating talks but Ryanair said its offer to meet the union one-on-one on Tuesday to try and solve their differences was pointless after another strike was called. Ryanair's pilots in Germany and the Netherlands have also voiced their support for the strikes launched by Ryanair's pilots in Ireland and could join the strikes any time in the near future, according to local media reports.
Ryanair says July 2018 saw more than 1,000 flights cancelled, compared to just 23 in July 2017.
Ryanair has confirmed that 100 pilots will take industrial actions tomorrow, with Irish passengers facing a fourth day of strikes.
Its shares fell further on Thursday and were down 3.6 percent at 13.02 euros by 1525 GMT, their lowest level since November 2016 and 8 percent below the level hit in December when Ryanair shocked the markets by recognising unions.
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The Dutch Airline Pilots Association (ALPA) voted in favour of industrial action, following in the footsteps of their German and Irish colleagues.
"This fifth strike notice by FORSA is irresponsible, unwarranted and is disrupting customers and is a way of damaging Ryanair's business", Ryanair Chief Marketing Officer Kenny Jacobs said in a statement. Ryanair said the walkout has had no effect on its service as on 24 of the 300 flights to and from Ireland were cancelled a week ago.
"Ryanair's refusal to recognize SEPLA and to apply the Spanish labor legislation to its pilots operating in Spain forces the union to use the judicial route to achieve this objective", it said.
Ryanair said in the statement that it was this tiny handful of Aer Lingus pilots who were behind the scenes for inciting the strikes and sabotaging the talks.
Ryanair did not respond to a request for immediate comment.