Aug. 10 (UPI) -- Almost 400 flights were canceled Friday amid a Ryanair pilot strike, affecting thousands of passengers that had flights scheduled in Germany, Ireland, Belgium and Sweden.
Ryanair pilots in the Netherlands are also on strike Friday, but no flights were cancelled as a result.
The European budget airline said about 15 percent of its flights were cancelled because of the strike, which affected about 50,000 passengers
The latest action by pilots is the latest in a series of strikes over pay and work conditions, something airline officials say they have made every effort to resolve.
In December, Ryanair faced its first strike in the company's 32-year history as pilots walked off the job over bids to earn union recognition and reach labor negotiations.
The strike was short-lived because the airline company agreed to recognize unions for the first time in its history but protests over labor agreements have continued since.
Last month, Ryanair strikes led to at least 300 flight cancellations as crews in Spain, Portugal and Belgium went on strike for 48 hours.
Unions want Ryanair contracts to be governed by laws where employees are based, not by laws in Ireland, where the company is based.
Ryanair apologized to its customers for the disruption and called for unions to continue negotiations instead of calling anymore strikes.
The company tweeted, "The majority of customers affected have already been re-accommodated on another Ryanair flight."