ATLANTA (Reuters) - Budget air carrier Norwegian Air (>> Norwegian Air Shuttle ASA) hopes to soon get U.S. government approval to operate more lower-cost flights to Europe despite opposition from U.S. and European unions, its chief executive said on Thursday.

The carrier is looking to increase flights between the United States and Europe with a new unit based in Ireland. The subsidiary, Norwegian Air International, was certified as an air carrier by the Irish government last month and still requires approval as a foreign air carrier from the U.S. Department of Transportation.

The U.S. clearance is the remaining hurdle Norwegian faces to operating the flights, which would be governed by an open-skies agreement between the United States and the European Union.

The carrier already operates flights to Europe from U.S. cities such as New York and Fort Lauderdale, Florida. The flights Norwegian plans to operate under its new unit include service between New York and London's Gatwick airport.

"We don't expect that the United States will treat Norwegian differently," Chief Executive Bjorn Kjos said in a telephone interview with Reuters.

An official with the U.S. Department of Transportation said in an emailed response that Norwegian's application was being considered, but gave few further details.

"We are in the midst of a contested proceeding and we are not in a position to address timing issues at this time," the official said.

U.S. unions have criticized Norwegian's plan, saying the carrier is looking to operate these longer-haul flights as an Irish airline in a bid to sidestep Norway's more stringent employment laws. U.S. airlines have also expressed concern about the plan.

The Air Line Pilots Association, European Cockpit Association and AFL-CIO unions have urged the United States to deny Norwegian's application.

Lee Moak, president of the Air Line Pilots Association, which represents nearly 50,000 pilots in the United States and Canada, told an aviation gathering in Washington this week that Norwegian's Irish unit was created to allow the company to reduce labor standards for workers.

By doing so, the airline was able to gain an unfair advantage over European and U.S. carriers in attracting passengers flying to and from the United States, Moak said.

This week, 38 U.S. senators sent a letter urging the transportation agency to make sure the Norwegian arrangement does not undermine a provision of the open-skies pact that suggests new flight opportunities spurred by the agreement should uphold high labor standards.

"We support competition and increased consumer choice, but not by unfairly disadvantaging U.S. airlines or threatening U.S. jobs," the March 12 letter from the senators states.

Kjos said the unions that oppose his carrier's plans were merely looking out for their own interests.

"They are just trying to stop competition because they hate to see that people are able to get low fares across the Atlantic," he said. "The fares are way too high across the Atlantic."

Kjos said he felt Norwegian was operating within parameters of the open-skies agreement between the EU and United States in setting up its long-haul operations.

He said he welcomed plans by any other low-fare carriers that might also want to add flights between the United States and Europe. "We should always have as much competition as possible," Kjos said.

(Editing by Andrew Hay)

By Karen Jacobs

Stocks treated in this article : The Boeing Company, Norwegian Air Shuttle ASA