Ryanair canceled scores of European flights on Friday but downplayed the impact of a strike that unions hoped would be the biggest in the airline's history.
The Dublin-based carrier insisted that the disruption to customers was limited, but unions claimed that they had halted more than the 190 flights listed as cancelled on the Ryanair website.
Many cabin crew walked out in Germany, Belgium, Italy, the Netherlands, Portugal and Spain and in some countries pilots' unions also took action.
"Today, over 2,150 Ryanair flights (90 percent of our schedule) will operate as normal, carrying 400,000 customers across Europe," the airline said.
In Belgium, 48 flights were cancelled, about half of those planned, according to figures provided by the two airports used by the low-cost carrier.
"Some cabin crew staff earn 2,000 euros, and you have a colleague who does exactly the same work, who only earns 1,000 euros, and with 1,000 euros in Belgium, it is impossible to live," Yves Lambot of the CNE union in Belgium said.
Tensions ran high at Eindhoven Airport in the Netherlands, where some passengers had already passed though security when a flight to London was cancelled with just half-an-hour until take-off.
The Dutch union VNV said it was seeking to take legal action to prevent Ryanair from bringing pilots in from abroad to replace striking Dutch crews.
In Spain, unions said 88 flights had been cancelled, affecting 15,000 passengers, mainly at Valencia, Palma and Alicante airports.
"The strike is taking place without any significant incidents", the Spanish Transport Ministry said.
At Porto airport, where Ryanair has its main base in Portugal, about 10 people were queueing on Friday morning in front of the airline's counter to find alternatives to cancelled flights.
"The company has provided a bus. It's not that comfortable. Instead of 50 minutes, the trip will take five hours. But at least I will arrive today," one traveller told Portugal's SIC television.
In Italy, "the movement is constantly expanding... Ryanair's approach to employees and trade union representation is wrong," unions said, adding that about 50 flight cancellations in the country.
Most affected customers received email and text message notifications on Tuesday to advise them of cancellations and options, Ryanair said.
Trade unions hope that Friday's 24-hour stoppage will be the biggest strike in the Irish carrier's history.
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.
- Workers' rights -
A 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 crew 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.
At a press conference the same day, O'Leary called for cancellation of the strike, threatening that he would shrink Ryanair's fleet at two Brussels airports if it went ahead.
Last month, Ryanair pilots across Europe staged a coordinated 24-hour stoppage 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.
The UK's Civil Aviation Authority has called on Ryanair to compensate passengers affected by the strikes.