Scandinavian low fares airline Norwegian carried more than 2.1 million passengers in May, up by 12% over the same month last year.
But strike threats from labour union Parat affected the carrier’s revenues as many people in Norway and Denmark refrained from booking flights due to fear of industrial action.
The load factor was the same as May 2013 at 77%.
Chief executive Bjørn Kjos said: “May was an atypical month where the strike threats from the labor union Parat affected our company considerably through fewer bookings and consequently lower revenues.
“On the positive side, I’m pleased that we keep attracting new customers, particularly in new markets outside Scandinavia.
“Norwegian’s on-time performance is almost 90%, making us one of most punctual airlines in Europe.”
Norwegian operated 98.8% of its scheduled flights in May, with 90% departing on time.
The airline took delivery of a new Boeing 737-800 and a 787 Dreamliner in the month.
Norwegian will take delivery of 14 Boeing 737-800s and four Dreamliners this year.
The figures emerged after Norwegian accused competitors and unions as using “foul play” trying to stop the airline expanding low cost transatlantic flights.
Norwegian accused the US Airline Pilots Association, other unions and several US airlines of making a number of “false and misleading allegations” about the airline to the media, the US Department of Transportation and members of Congress.
“This is a frantic attempt at blocking competition, consequently preventing the American people access to affordable airfares to Europe and blocking the creation of new jobs in America,” Norwegian said.
Norwegian said it had carried 100,000 American passengers to Scandinavia on its fleet of Dreamliners and 200,000 passengers to the US in the past year.
The airline has sent up a long-haul division in Ireland and plans to start low fare flights from Gatwick to the US.