Dale Vince is one of the main supports of Just Stop Oil, you know, the vicars etc who are blocking the roads around the capital.
So this current pie in the sky idea is about creating an argument / reason to ban oil extraction from the North Sea, rather than any real business case for green aircraft.
You can bet that now its all about sound bites that he and his cohort can shout at the cameras as a distraction to their ridiculous ill conceived plan to cripple parts of the UK economy.