Ryanair is now facing strike action by pilots in five countries tomorrow as part of a 24-hour stoppage.
Pilots based in the Netherlands were the latest group to join the action when they announced last night that efforts to reach a collective labour agreement had failed.
The company is expected to ask a Dutch court later today to halt the action by the Dutch pilots' union.
Pilots are also set to strike in Ireland, Sweden, Belgium, and Germany.
Professor of Employment Law at Maynooth University, Michael Doherty, says the while the issues are not the same in each country, the action is designed for collective impact.