A Norwegian Air Boeing 787. Norwegian Air On Thursday, President Donald Trump met with leaders from the airline industry, and it's possible that one of the topics discussed was the controversial arrival of Norwegian Air International.

In December, the US Department of Transportation finalized its decision to grant NAI approval to operate flights into the US.

"This case is among the most novel and complex ever undertaken by the department," the DOT said in its final ruling on the matter. "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."

Many in the US airline industry, especially the unions that represent pilots and flight attendants, would like to see the Trump administration overturn the decision. But it's unclear what action, if any, the Trump administration would take against Norwegian.

White House press secretary Sean Spicer indicated on Tuesday that the deal with Norwegian involves the hiring of large numbers of US-based pilots and cabin crew. Spicer also said that as a major customer for Boeing airplanes, Norwegian has significant economic interests in the US.

"We are a big Boeing customer, so I think we do exactly what Trump would like everybody to do," Norwegian Air CEO Bjoern Kjos told Reuters on Wednesday. "Trump wants American jobs. We provide American jobs."

Norwegian currently operates about 120 Boeing 737 and 787 airliners, with another 120 or so Boeing jets on order.

NAI is one of several subsidiaries operating under the Norwegian banner. Unlike the rest of Norwegian, NAI is based in Dublin, instead of in Norway. Critics say this allows NAI to take advantage of Ireland's employment laws, which are significantly less stringent than Norway's. As a result, they say, NAI could hire pilots and cabin crew members from Asia at lower wages to fly transatlantic routes.

The airline operates flights into the US using its Norway-registered Norwegian Long Haul subsidiary with Europe-based pilots and crew.

In a December statement, Edward Wytkind, president of the AFL-CIO's Transportation Trades Department, wrote:

"Today's decision betrays America's aviation workers by granting a rogue, flag-of-convenience airline a permit to serve the United States. Unless reversed, this decision threatens a generation of US airline jobs and tells foreign airlines that scour the globe for cheap labor and lax employment laws that America is open for business. Clearly, a Norwegian-owned airline that is based in Ireland for the purpose of evading Norway's labor and tax laws, and that will hire crews under Asian contracts, is in violation of these explicit labor protections and should be denied entry into our marketplace."

The Air Line Pilots Association, a union that represents 54,000 US and Canadian pilots, echoed the AFL-CIO's aggravation.

"We are extremely disappointed by the Department of Transportation's decision to run roughshod over the US Open Skies agreement and allow Norwegian Air International to fly to and from the United States," ALPA President Tim Canoll said in a statement. "This decision is an affront to fair competition and will ultimately result in the loss of US jobs and, potentially, significant losses for the US international aviation industry."

A Norwegian Air Boeing 787-8 interior. Norwegian

In light of the DOT's ruling, Norwegian announced in December it would ramp up the hiring of American pilots and cabin crew.

"In October this year, Norwegian announced it would open its first US pilot base at Fort Lauderdale-Hollywood International Airport," Kjos said in a statement. "Now that we finally have our DOT approval for Norwegian Air International, I'm pleased to announce that we will also be opening a second and third pilot base in the US."

The second and third crew bases will be in the New York and Greater Boston areas, Norwegian Air representative Anders Lindstrom told Business Insider. The initial group of 25 US pilots destined for the base in Fort Lauderdale, Florida, will begin training in March to fly the airline's fleet of Boeing 787 Dreamliners.

Once the airline's new 737 MAX 8 airliners enter service in the middle of 2017, Norwegian is expected to hire another batch of US pilots for the New York and Greater Boston bases.

According to Lindstrom, all pilots hired for the new US bases are either flying for another US airline or are American pilots flying overseas. Lindstrom also told Business Insider in April that the airline pays all its pilots "almost exactly" the same, regardless of where they are based.

The airline said its New York base would have more than 300 cabin crew members by year's end, while its Fort Lauderdale base would have nearly 200.

Norwegian expects to hire another 150 pilots and cabin crew members in the US in 2017. In 2018, Norwegian is eyeing the possibility of additional pilot and crew bases in Oakland, California, and LAX, Lindstrom said.

Norwegian Air CEO Bjorn Kjos in the cockpit of a Boeing Dreamliner. Norwegian

When the Boeing 737 MAXs arrive later this year, Norwegian will begin offering $69 tickets to Europe from secondary cities in the northeastern US. Norwegian Air CCO Thomas Ramdahl told The Wall Street Journal in December that the airline intends to set up a base at Stewart International Airport in upstate New York, and Bradley International Airport in Hartford, Connecticut, is also under consideration.

In 2017, the airline is expected to receive nine 787s, six 737 MAXs, and 17 737 NGs. Norwegian — which in July was named the best low-cost airline in Europe by Skytrax for the fourth consecutive year — operates 450 routes with 150 destinations around the world.

Skytrax reviewers also named Norwegian the best long-haul low-cost airline in the world.