With a goal of reducing total fuel burn by 30% or more, NASA has contracted with Boeing to develop two full-scale prototypes of narrow-body airliners using the transonic truss-braced wing concept to increase the aspect ratio (wing span to chord) of the plane’s wing, supporting it by a truss which will also generate lift. NASA is spending US$ 425 million of money borrowed by the insolvent state for which it works, while Boeing (which is carrying US$ 77.3 billion in debt on its balance sheet) and its partners are “investing” US$ 725 million in the project.
The wings will be so long that a production plane based upon the design will require hardware to fold them beyond the strut attachment point so the aircraft can use taxiways and gates designed for narrow body aircraft. I have not seen a statement whether or not the experimental planes will incorporate wing folding. The fuselage and landing gear will be adapted from the discontinued MD-90 airliner, acquired when Boeing merged with McDonnell-Douglas in 1997.