US aerospace giant Boeing on Wednesday finalized an order with Thai budget airline Nok Airlines for 15 737 aircraft, worth $1.45 billion at list prices. Nok Air is buying eight Next-Generation 737-800s and seven 737 MAX 8s, and plans to convert one of the 737-800s into a 737 MAX order at a later date, the companies said in a joint statement. The order was first announced as a commitment at the Singapore Air Show in February. Nok Air currently operates a fleet of 15 Next-Generation 737s. "The 737 is the backbone of our fleet and has fueled our growth over the past 10 years," said Nok Air's chief executive, Patee Sarasin. "This order is a key part of our disciplined fleet strategy. These 737s ensure that Nok continues to operate the most reliable and fuel-efficient aircraft on the market today and in the future." Nok Air will be the first airline in Thailand to operate the 737 MAX, an update of Boeing's Next Generation 737 that offers better fuel efficiency, lower emissions, and a farther range, up to 6,667 kilometers (4,142 miles). Boeing expects the first one to fly in 2016.