On January 8, 2019, Boeing revealed Transonic Truss-Braced Wing concept, aimed to “higher and faster” that previous concepts of such wing.
The ultra-thin, folding wing has a span of 170 feet (approximately 52 metres) and is made possible by a truss, which supports extended length of the wing.
Originally the wing was intended for flying at a speed of Mach 0.70 – 0.75, Boeing states, but it has been increased to Mach 0.80, getting closer to the speed of sound (Mach 1). The cruise speed was improved by optimizing truss and modifying wing sweep.
The wing is still at conceptual phase. The design is part of Subsonic Ultra Green Aircraft Research program, that Boeing has been carrying out with NASA for nearly a decade now.