The boss of European low-cost carrier Norwegian has denied claims by US unions that it will undercut their crews on pay and working conditions.

Bjørn Kjos spoke out in the face of ongoing opposition to the airline’s plans to extend transatlantic operations with a new airline flying under the British flag.

The carrier won approval from the Civil Aviation Authority to launch Norwegian Air UK when it was handed an operator’s certificate in November.

That should allow it to take advantage of Britain’s free movement treaties, including the open skies arrangement between Europe and the US.

Norwegian runs no-frills flights from Gatwick to a number of US cities and wants to dramatically increase its transatlantic routes.

But its application to the US Department of Transportation faces opposition from unions, including the Air Line Pilots Association, which represents Delta Air Lines crews, and American Airlines’ union, the Allied Pilots Association. They have been joined in their complaint by SAS and Air France-KLM.

Kjos told the Sunday Times: “We don’t get pilots and cabin crew if we don’t pay the going rate. It’s just so stupid that they are trying to govern UK labour laws.”

He added: “The only thing I can see is that they are trying to stop competition. They know that when we come in, the fares will go down.

“Legacy carriers tried to keep easyJet and Ryanair out of the market in Europe. Now they are afraid of low fares across the Atlantic.”

Kjos said that Norwegian would also use the UK licence to start passenger services to other long-haul destinations, such as South America.