The main obstacle for long-haul operators is weight. Two decades before the Wright brothers’ first flight in 1903, a two-man crew took the airship La France on the first round trip by an aerial vehicle.It carried a 435kg zinc-chlorine battery on its 8km journey – the equivalent of hauling around a grand piano.

A modern battery this massive would still provide only a fraction of the power required for a commercial passenger aircraft with 150 or more seats.

In January Carnegie Mellon University’s Prof Venkat Viswanathan wrote an article for Nature on the future of batteries in aviation which has become a call-to-arms for engineers in the industry. Viswanathan and his coauthors concluded that it was possible to make significant gains in battery chemistry for use in aviation by 2030 – but only if everything went right along the way. And even then, they would still not be capable of powering the largest passenger aircraft.