A new method of building metal things that only weigh as much as foam things is being instigated by the tube-makers at Boeing, who claim that their new "microlattice" metal structures have all the strength of traditional metal but virtually none of the weight.
According to Boeing's engineers, this system results in a metallic structure that's actually 99.9 per cent air. They describe it as a being 3D polymer structure built with a nickel-phosphorus alloy, one that's assembled like a human bone, with a honeycomb-like central structure of 100nm thick cells surrounded by a rigid shell. The hope being that it could lead to lighter aircraft that use less fuel in the future.
Boeing has stuck up a video explaining the whole bone/lattice/metal concept on YouTube, which is going under the modern title of Lightest. Metal. Ever. -- here it is: