“Travelling in the Sky Whale could be like a travelling in your private ‘theatre seat’, enjoying what happens around you; hearing some air flow noise, but feeling safe inside a big and intelligent structure,” Vinals says.

The design would use advanced technologies such as self-repairing wings, swiveling engines to enable a near vertical take-off, and hybrid propulsion.

“The engines and batteries are fed by a turbine inside the wings, like a high-speed and powerful dynamo,” says Vinals.

The design also calls for a system to redirect air flow to intake engines and to control laminar flow – in other words, to reduce turbulence around the plane and reduce drag.

None of these technologies are feasible on a large scale at the moment, but all are possible, says Vinals.

“I did this because I am an aerospace and aviation enthusiast – the technology, development and evolution,” he explains. “I would like to contribute, with my vision, about these.”

Perhaps that vision from someone outside the aerospace industry, without preconceptions, is what is needed to revolutionise plane design. Vinals told me he did “years” and “terabytes” of research. It’s an approach that some in the field appreciate.

“I think that’s where these concepts come in,” says Dr Michael Jump, lecturer in aerospace engineering at the University of Liverpool. “It’s people challenging through their imaginations. It’s the engineering community’s opportunity to either say ‘that’s a good idea, let’s try and make it happen’, or ‘it’s less of a good idea, and this is the reason why’”.

He says there are three factors to consider when evaluating the design of an aircraft, collectively known as the Breguet Range equation. This can be used as an estimate of efficiency.