Norwegian Air already bills itself “world’s fastest-growing airline,” and the European budget airline is backing that up with yet another round of expansion from the United States.

Austin and Chicago O’Hare will join the carrier’s route map next spring and Norwegian will add more European routes from cities it already serves -- the growth furthering what’s been a torrid growth spurt for the airline in the U.S.

“We are excited to add two more U.S. cities to our ever-growing network," Bjørn Kjos, Norwegian’s CEO, said in a statement. "We will now offer nonstop service from 15 U.S. cities to 13 European cities, no other airline can rival that."

"We are excited to add Chicago and Austin to our ever-growing U.S. network," Bjørn Kjos, Norwegian’s CEO, said in a statement. "We will now offer non-stop service from 15 U.S. cities to 13 European cities, no other airline can rival that. Within just a year, we have added seven U.S. gateways, creating much greater access for even more Americans to save a tremendous amount of money."

From both Austin and Chicago, Norwegian will launch non-stop flights to its base at London’s Gatwick airport this spring. The carrier will offer four flights a week from Chicago (starting March 25) and three a week from Austin (starting March 27). The new service on Boeing 787 Dreamliners will launch with fares starting at $174 one way from Chicago and $249 from Austin.

Beyond the two new cities, Norwegian also is adding more destinations from U.S. cities it already serves. The airline will add routes to Paris from Boston, Newark and Oakland, growing its footprint in each of those cities.

With the new Paris flights, Norwegian will fly to a total of seven European routes from Oakland. The carrier also serves the San Francisco Bay Area airport with flights to Barcelona, Copenhagen, London Gatwick, Oslo, Rome and Stockholm. From Boston, the Paris flights will become Norwegian’s fourth European destination, joining Copenhagen, London Gatwick and Oslo.

Norwegian also will beef up its Paris schedule by adding more flights on its existing service from Los Angeles. And when Norwegian's six weekly Newark-Paris flights begin Feb. 28, they'll compliment the carrier's existing daily service to Paris from New York JFK.

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In total, Norwegian will fly six non-stop routes between the USA and Paris once the Boston and Oakland routes launch. The carrier’s U.S. reach from London is even bigger, with Norwegian now flying non-stop from Gatwick to 11 U.S. destinations.

The new routes and added frequencies serve to underscore Norwegian’s breakneck growth in the U.S. market, where the carrier debuted only about four years ago.

Now, with the new service announced Wednesday, Norwegian will offer 56 different trans-Atlantic flights from 15 U.S. airports to 13 destinations across France, Ireland, Norway, Spain, Sweden and the United Kingdom. Norwegian’s tally of U.S. routes grows to 62 when its service to the French Caribbean islands of Martinique and Guadeloupe is counted. The carrier flies to the islands from New York JFK, Providence and Fort Lauderdale.

Norwegian is growing elsewhere, too. Flights between London and Singapore are set to begin later this year while London-Buenos Aires flights have been announced for next year.

Still, its Norwegian’s ambition in the U.S. that remains front and center.

It was just last week that Norwegian took the first of more than 100 Boeing 737 Max jets it has on order. Norwegian intends to use the aircraft – Boeing’s latest update to its best-selling 737 model – to launch a whole raft of new trans-Atlantic flights.

Norwegian has detailed plans to use the 737 Max to fly to Europe from small U.S. airports where costs are lower. Coupled with the fuel efficiency and economics of the modern Max-8, Norwegian founder and CEO Bjørn Kjos is betting the aircraft will allow Norwegian to make money on niche routes like Providence-Cork, Ireland, and Newburgh, N.Y.-Edinburgh, Scotland.

Norwegian has already launched the first of 12 such routes it will fly from Providence, Newburgh and Hartford, Conn. By the end of the summer, Norwegian will be flying non-stop from those U.S. cities to a half-dozen destinations in Ireland, Norway and the United Kingdom.

“The Max-8 will pave the road for a totally new concept,” Kjos. “It gives us the ability to open up routes between the Europe and the U.S. on a totally new fare basis.”

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