Chief among them is the airframe. The faster a plane flies, the louder it roars. So Graham and his group designed the SAX-40 with a blended-wing body, a concept that jettisons the tube-and-wing approach for a tailless, triangular structure. That shape provides extra lift, enabling the plane to fly more slowly during takeoff and landings. It also saves a significant amount of fuel, getting some 35 percent more passenger-miles per gallon than a Boeing 777.