The new X-plane seeks to enable a potential new generation of more sustainable single-aisle aircraft ?" the workhorse of passenger airlines around the world. Working with NASA, Boeing will build, test, and fly a full-scale demonstrator aircraft with extra-long, thin wings stabilized by diagonal struts, known as a Transonic Truss-Braced Wing concept. The X-66A will validate technologies for a Transonic Truss-Braced Wing configuration that, when combined with other advancements in propulsion systems, materials, and systems architecture, could result in up to 30% less fuel consumption and reduced emissions when compared with today's best-in-class aircraft.