The zero-emissions plane

The Economist: When an airliner takes off for a transatlantic flight it needs to carry some 80 tonnes of fuel, which accounts for around one-fifth of its weight. On really long flights, fuel can account for 40% of a plane’s take-off weight, so that around 20% of the fuel is used to carry the rest of the fuel. Each tonne of fuel burned also produces 3.2 tonnes of carbon dioxide.

Yet inside a hanger at a Swiss airfield is the prototype of an aircraft that does not use any fuel at all. The wings of this aircraft are almost as big as those of an airliner, but they are covered in a film of solar cells that convert sunlight into electricity to drive its engines.