Boeing Co. secured a $1.3 billion order for narrow-body planes from Okay Airways, with the Chinese regional carrier set to decide on its first wide-body order by the end of the year as it seeks to expand internationally. Okay Air agreed to buy 12 single-aisle 737s, with an option to purchase eight more, Chicago-based Boeing said in a statement distributed at the Singapore Airshow Wednesday. The Chinese carrier, which is headquartered in Beijing and counts Tianjin as its hub, is purchasing eight 737Max-8, three 737MAX-9 and one 737 NG900-ER. The purchase on the second day of the Singapore Airshow comes amid speculation that the heyday of big orders from India and Southeast Asia is ending, and that airlines in the region might have to delay delivery of planes as economic growth slows. Boeing expects China to overtake the U.S. as the world's biggest aviation market in 20 years. Okay Air Chairman Wang Shusheng told reporters Wednesday that the airline needs more planes with its load factor at 90 percent. The carrier plans to fly to Hawaii and Fiji using wide-body planes, and will decide between Airbus Group SE's A350 and Boeing's 787 by the end of the year, he said. Okay Air's deal comes two months after Boeing landed an order for 110 planes valued at $10 billion in list prices from state-owned China Southern Airlines Co. In September, Boeing inked a deal to build a finishing plant for single-aisle planes in China.