Could the 'flying piano' help transform air cargo?

Regulators are likely to be cautious as well, particularly in the US, where the Federal Aviation Authority is under pressure after serious problems with Boeing aircraft.

Mr Graetz replies that his team has complied with every request from the FAA so far. “The FAA has always been super risk averse. That’s their business!”

Fred Lopez spent 36 years in aviation operations at cargo giant UPS. As he says, he’s put “my entire adult life” into working out the most cost-effective way to operate an air freight business.

Mr Lopez admits he was profoundly sceptical about cargo gliders when Aerolane first approached him. But the prospect of serious fuel savings won him over and now he sits on their advisory board.

Cutting fuel costs is an obsession in civil aviation. When the upturned wing-tips we see out of a cabin window became a standard design feature airlines cut fuel costs by around 5%.

But gliders only consume the fuel required by their tow plane. If that too is a cargo aircraft, a pair of gliders drawn by one jet represents a significant reduction in fuel consumption on a large shipment.

The initial Aerolane design uses their autopilot plus what Mr Lopez terms a human “safety pilot”. This should make certification from the FAA easier.

“Aerolane is not trying to change everything at one go” he says.

Their ultimate goal is autonomous operation using AI, or as Mr Lopez puts it “to pull the pilot out of the seat".

And, if the flying piano can surf, then who knows what's possible?