Airplanes are wonderful things when they actually fly. Later this year Boeing will see whether its newest aircraft can do just that when it conducts the first test flight of its 787 twin-engine Dreamliner. After several years of losing aircraft orders to European rival Airbus and chasing fantasy airplane ideas like the Sonic Cruiser, which never got off the drawing board, much less the runway, Boeing is banking on the 787. So far, so good: the 787 is the most technologically advanced commercial airplane ever and the best-selling new airplane in Boeing's storied 90-year history. More than 37 customers including industry-leading Singapore Airlines and two U.S. carriers, Northwest and Continental have signed up to buy the plane. The 787 offers some gee-whiz selling points: Boeing says the plane is 20% more fuel efficient than today's like-sized planes and more comfortable too, because the interior cabin altitude will be lower than the current standard of 8,000 ft. A new environmental system will add more humidity to the usual dry interior air, and there may even be a window in the bathroom. Boeing says the 787 is on track to fly by August and start carrying passengers next year.