Can we travel the world without destroying it?

Are we due another revolution in human flight, one which powers air travel with zero-carbon technology? The great hope is that electric aeroplanes could oust the current fleet of commercial airliners which rely on fossil fuels.

Electric batteries are replacing combustion engines in road vehicles at such a rate that by 2030, electric cars are expected to make up one-third of the car market.

Meanwhile, most electric aeroplane prototypes are grounded on the drawing board. Venkat Viswanathan, Shashank Sripad and William Leif Fredericks – all experts in mechanical engineering at Carnegie Mellon University in the US – believe it’s because batteries can’t store as much energy per weight as liquid fuels. This, they say makes batteries relatively heavy for aviation. As they explain: