SEATTLE (AP) -- Aerospace manufacturer Boeing Co. on Thursday confirmed an order for an additional six more next-generation 737s for low-cost carrier Norwegian Air Shuttle.

The Oslo-based carrier now has a total of 48 737s on order from Boeing as well as 22 airplanes from leasing companies.

"As we expand our markets and provide more low-cost options for our rapidly growing customer base, it makes strategic sense that the 737-800 forms the bedrock of our fleet," said Norwegian CEO Bjorn Kjos.

Norwegian is one of the first airlines in Europe to incorporate the spacious new 737 Boeing Sky Interior starting at the end of 2010.

Shares of Boeing added 35 cents to $50.98 in afternoon trading.