The Boeing Next-Generation 737-900 takes off on its maiden flight from Renton Municipal Airport in Renton, Wash. The Boeing 737-900, the largest of the Next-Generation 737 models, is a derivative of the Boeing 737-800. The airplane, the first of 11 737-900s ordered by Seattle-based Alaska Airlines, now will participate in a six-month flight-test program. KLM Royal Dutch Airlines, Korean Airlines and Continental Airlines also have ordered the 737-900.