The US Department of Transportation (DOT) has granted controversial airline Norwegian Air International (Dublin International) a Foreign Air Carrier Permit (FACP) thus bringing to a close a drawn-out, and often acrimonious, authorization process.

In its decision finalizing a tentative ruling issued in April of this year, the regulator said the case was among the most "novel and complex" it had ever undertaken.

"We have taken the necessary amount of time to review and consider the comments from a wide range of stakeholders," it said justifying the three-year review process.

The DOT said that among the most difficult aspects of the case was the interpretation of Article 17 bis contained within the EU-US Open Skies Treaty. The clause governs labour standards.

Opponents to NAI's application had argued that its plan to employ cabin crew outsourced from a third-party company domiciled in Singapore, rather than directly employing personnel itself, undermined the terms of the Article and would violate the DOT’s statutory public interest goal of encouraging fair wages and working conditions. They argued this was sufficient grounds for the DOT to reject NAI's application, an argument the US Attorney General's office later refuted in its analysis of the treaty. It upheld the Department of State and the DOT's conclusion that so long as an applicant airline satisfied all the requirements for an FACP as prescribed under the treaty, Article 17 bis did not provide an independent basis upon which the US may deny the carrier’s application

"Regardless of our appreciation of the public policy arguments raised by opponents, we have been advised that the law and our bilateral obligations leave us no avenue to reject this application," the DOT said. "Therefore, ..., we have decided to make final our tentative decision to grant the request of NAI for a foreign air carrier permit."

The approval now sets a precedent for the issuance of an FACP to another of Norwegian's units, Norwegian UK (London Gatwick). In July, the DOT denied the UK-based carrier exemption authority in the face of strong resistance from airlines, trade unions, and lobby groups on either side of the Atlantic.

“We welcome the long overdue news that Norwegian Air International (NAI) has been awarded a foreign carrier permit by the US Department of Transportation," a Norwegian (Oslo Gardermoen) spokesman said. “This approval finally makes it possible for us to plan the Cork to the U.S. routes we, and many others, have been looking forward to. We also now look forward to our foreign carrier permit for Norwegian Air UK (NUK) being approved next."