Ryanair Chief Executive Michael O’Leary loves a good fight, and he’s won far more than he’s lost, building the Irish carrier into Europe’s biggest discount airline over the past 20 years.

But tiny Denmark could be O’Leary’s toughest adversary yet. Since introducing  service to Copenhagen this spring, Ryanair has come under nonstop attack from unions, government officials, and others who accuse it of violating workers’ rights in the Scandinavian country of 5.6 million people known for generous social protections.

In the latest round, Ryanair was summoned before a labor tribunal in Copenhagen on June 15 to defend the practice at the center of the controversy: its hiring of Denmark-based pilots and cabin crew on Irish labor contracts. Ryanair says the arrangement, which it uses in other countries, is legal, and that its Danish employees “enjoy high pay [and] job security.” Critics say it allows Ryanair to avoid rules on wages, social benefits, and worker protections required by Danish laws. The tribunal is reviewing the case and hasn’t said when it will rule.

This isn’t the first time Ryanair’s employment policies have come under fire in the courts. France fined the airline 9 million euros ($10.3 million) in 2013 for failing to make French social-security and pension contributions on behalf of local workers hired on Irish contracts. The Belgian air-transport association is challenging the use of Irish contracts for Ryanair crew based in Belgium.

The showdown in Denmark goes well beyond the courtroom. On March 18, Ryanair’s first departure from Copenhagen was delayed by three hours after protesters blocked the plane on the tarmac. Now, Danish pension funds and government investment agencies have joined the fray by unloading their Ryanair stock. The mayors of Copenhagen and several other cities have forbidden municipal employees to flying Ryanair on official business.

The fight has spilled over into social media. After Copenhagen Mayor Frank Jensen announced in May that the city’s 45,000 employees couldn’t use Ryanair for official trips, the airline lampoonedhim on its Twitter feed with a photo depicting him as Marie Antoinette and the caption “Let them pay high fares!” Jensen tweeted back that he was happy to be a symbol of support for good working conditions in Denmark. Some of his supporters went further, posting an image on Twitter of CEO O’Leary astride a Ryanair plane. It was labeled “Ryanair: Screwing Over Its Staff.” Hundreds of Danes have joined the online fray, with one recent tweet describing Ryanair’s leaders as “tax evading parasites of aviation” and another saying “Ryanair, go home!”

Ryanair has asked the Danish courts to bar protesters from disrupting its operations and says it has complained to the European Union about the restrictions on Danish municipal workers’ flying Ryanair. “These municipalities are breaking EU law by banning their staff from choosing Ryanair’s lowest fare flights,” Ryanair said in a statement. Mayor Jensen’s office says the city didn’t single out Ryanair, but merely applied a policy requiring it to do business only with companies that comply with Danish labor laws.

The battle comes as O’Leary triesto soften what he has described as Ryanair’s image as a “cheap and nasty” company. Profits have risen as the company has introduced more customer- friendly policies such as reserved seating, while scaling back charges for baggage and other extras.

For now, Ryanair says it is benefiting from the no-such- thing-as-bad-publicity rule. In a tweet headed “Thanks, Frank!” the airline said its Copenhagen passenger bookings jumped 45 percent after the online dustup with Mayor Jensen. “We are very pleased with the performance of our base at Copenhagen, and we look forward to continuing to grow,” spokesman Robin Kiely said.

—With Kari Lundgren

This article was written by Carol Matlack from Bloomberg and was legally licensed through the NewsCred publisher network.

Photo Credit: Ryanair's tweet about Copenhagen's mayor. Ryanair / Twitter