In a paper in the journal Smart Materials and Structures, the [NASA and MIT] research team explains how it has radically redesigned the airplane wing. Their new structure is a lightweight lattice framework, made of thousands of repeating, tiny triangles of matchstick-like struts, covered in a thin polymer layer. Because this “metamaterial” is mostly comprised of empty space, it is extremely lightweight — less than one-thousandth the density of rubber. And, the carefully positioned struts allow the wing to change shape automatically in response to changes in aerodynamic loading conditions. Both factors could make aircraft more energy efficient.