Low-cost airline Norwegian Air Shuttle has agreed to buy 42 of Boeing's "green" 737-800 passenger jets in a deal worth $3.1bn (£1.5bn).
The 737-800 is built to lower carbon emissions and reduce fuel costs
The planes are scheduled for delivery between 2009 and 2014 and the order follows a previous deal with the airline for 11 737-800s in May.
The planes were designed to cut carbon emissions and reduce fuel costs.
Existing versions of the plane are under scrutiny after a China Airlines 737-800 exploded in Japan this month.
Norwegian said it had also secured the rights to buy 42 similar models from Boeing.
The value of the overall order, which is currently quoted at list prices, could change.
But analysts said the order was a bold step for Norwegian, a much smaller operation than its main rival, the Scandinavian carrier SAS.
"This is the largest order in Europe received by Boeing for the company's 737 series thus far in 2007," the Nordic firm said in a statement.
It added that fuel consumption would be cut by up to 33% and nitrogen oxide emissions by up to 43% compared with the oldest planes in Norwegian's current fleet.