Lighter aircraft can carry more weight with less fuel, which is why the airline industry is constantly researching new materials. The latest is a metal consisting of 99.99% air, developed by engineers at Boeing.
They've called the material 'microlattice', because it consists of a network of tiny tubes with a wall thickness of just 100 nanometres. It's made by an etching process, where a template is created, covered with nickel plating, and then removed with chemicals.
As you can see, the result is a material that's incredibly lightweight and has a high degree of flexibility -allowing it to be depressed and bounce back. That's a handy feature to have on planes, which have to be flexible to cope with turbulence.
It's unlikely to be used as a major structural component immediately, Boeing says. Instead, it'll be used inside the cabin - under the floor, in overhead lockers, or as part of other fixtures.