Ryanair chief executive Michael O'Leary has dismissed a union call to boycott the airline, claiming his employees are better paid and work under better conditions than those at many unionised carriers.
Last week Swedish trade union HTF handed out sick bags to passengers flying on Ryanair from the city of Nykoping - 160 km south west of Stockholm - as part of a wider campaign organised by the International Transport Workers' Federation (ITF).
The white bags were printed with claims that Ryanair staff had to work longer and for lower pay than rivals.
Speaking at a Stockholm press conference, O'Leary said Ryanair paid more on average to staff and that its rules on the maximum hours staff could work were the strictest in the industry.
"We are an embarrassment to a lot of trade unions," he said.
Ryanair staff earn an average of €50,582 a year, more than staff at airlines where staff are unionised, O'Leary added.
The average for Scandinavian airline SAS - which until an agreement this year to cut wages and extend working hours, had to deal with 39 trade unions - was lower at €50,425, according to figures provided by Ryanair.
Most Swedish workers belong to trade unions, but Ryanair is non-unionised. The airline promises to pay more than union rates if its employees negotiate their contracts directly with the company rather than join unions for collective bargaining.
"Ryanair is a high-pay airline," O'Leary said.
The HTF, which represents around 160,000 white collar workers - including cabin attendants and ground staff - in Sweden, dispute Ryanair's figures.
"We consider the terms of employment to be under the level for the market in Sweden," said HTF's Michael Collins, who said Ryanair's salary levels were probably distorted upwards because it employs fewer lower-paid ground and technical staff than companies like SAS.
Although total working hours are limited annually, Collins said Ryanair employment contracts could result in brief periods during which some staff are required to work long hours "to a level that is not to be tolerated."
An SAS spokesman said he was doubtful about Ryanair's claims. "We don't know exactly how much they earn at Ryanair ... but we are a bit sceptical," said Bertil Ternert.
"We have a lot of technical and ground staff and have more and different kinds of work than Ryanair," Ternert said, referring to Ryanair's heavier use of outsourcing and smaller operational scope as a Europe-only, low-fares carrier.
At the press conference O'Leary said Ryanair, which expects to carry its 100 millionth passenger within the next few months, would sue Swedish newspaper Dagens Nyheter unless it retracted reports critical of some aspects of Ryanair's safety record.
"Nothing is more important to us than safety," he said.
"If we don't receive a retraction we will initiate legal proceedings against it (the newspaper)," O'Leary said.