I mean that if we could get the most unforeseen ideas implemented to an electric aeroplane...how far are we from this perfect situation ? I assume it means: 1. New structural ideas 2. Better engines 3. Battery developement 4. Aerodynamical innovations This is very necessary to get developement fast..as the energy density of batteries is about 1/20th at the best cases from fuel. I think we can make 65-70 % progress compared to the systems today flying....in 10 years. Electric engines are simple and light...which is a good thing ( I opened one ).