The Dublin-based carrier said that it would cancel six percent of flights amid the walk-outs in Belgium, Italy, the Netherlands, Portugal and Spain. It had previously estimated 190 would be affected.

Germany’s pilots’ union said it would support the strike action, while the country’s cabin crew union said it would announce on Thursday evening whether German Ryanair crew would join Friday’s walkout.

Trade unions have claimed that Friday’s 24-hour stoppage will be the biggest strike in the Irish carrier’s history.

Ryanair said in a statement that the vast majority of its 2,400 flights on Friday “will be unaffected by these unnecessary strikes and will operate as scheduled”.

All affected customers received email and text message notifications on Tuesday to advise them of cancellations and options, Ryanair said.

“We sincerely apologise to those customers affected by these unnecessary strikes on Friday which we have done our utmost to avoid,” it said.

Ryanair staff have been seeking higher wages and an end to the practice whereby many have been working as independent contractors without the benefits of staff employees.

Another key complaint of workers based in countries other than Ireland is the fact that Ryanair has been employing them under Irish legislation.

Staff claim this creates huge insecurity for them, blocking their access to state benefits in their country.

EU Social Affairs Commissioner Marianne Thyssen said on Wednesday air crews should be employed under contracts from the country where they work.

“Respecting EU law is not something over which workers should have to negotiate, nor is it something which can be done differently from country to country. I made this very clear to Mr O’Leary today,” Thyssen said in a statement after a meeting between Ryanair’s combative chief executive Michael O’Leary and EU officials.

“The internal market is not a jungle; it has clear rules on fair labour mobility and worker protection. This is not an academic debate, but about concrete social rights of workers.”

At a press conference O’Leary called for the cancellation of the strike, threatening to shrink Ryanair’s fleet at two Brussels airports if it went ahead.

Last month, Ryanair pilots across Europe staged a coordinated 24-hour strike to push their demands for better pay and conditions, plunging tens of thousands of passengers into transport chaos at the peak of the busy summer season.

In July, strikes by cockpit and cabin crew disrupted 600 flights in Belgium, Ireland, Italy, Portugal and Spain, affecting 100,000 travellers.

This week, Ryanair signed deals with cabin crew unions in Italy to provide employment contracts under Italian law. DM