The US Department of Transportation (DoT) provisionally approved Norwegian’s application to start flights through its Irish subsidiary in April, but had not given final approval despite the request being filed more than two years ago.

The application was approved by Washington on Friday December 2.

The plan had divided the industry as airlines and unions on both sides of the Atlantic battled over whether it would increase competition or unfairly harm other carriers and their workers.

Norwegian already operates trans-Atlantic flights from Scandinavia, London and other European cities using its Norwegian license, but has far fewer services than airlines such as and Air France-KLM SA, which vigorously opposed Norwegian’s application.

Norwegian chief executive, Bjorn Kjos, said: "We welcome the long overdue news that Norwegian Air International has finally been awarded a foreign air carrier permit by the US Department of Transportation.

“The decision paves the way for greater competition, more flights and more jobs on both sides of the Atlantic.

“Above all, it is a victory for millions of passengers who will benefit from more choice and lower fares.

“We now look forward to continuing our global expansion, delivering new routes, more jobs and economic boosts.”