You can do small aircraft like this, no problem. The trouble is you can't scale it up, due to how quickly the power and energy demands go up. This thing is 560 kW and gets a range of 86 nmi; an A320 is around 40 000 kW and has a range of 3 500 nmi, while an A380 is around 80 000 kW and has a range of 8 500 nmi. Going from this DHC-2 to the A380 requires an increase in energy storage by a factor of around 14 000x, whi…
1. DHC-2 takes 6 people 86 miles ~= 500person/miles
2. 747 potential battery payload ~= 200,000kg (fuel capacity)
3. Power capacity of 200,000kg lithium-in ~= 25MW hours
4. Power required to take off, assuming 2.5 minutes to reach cruising altitude ~= 90MW * 2.5 / 60 ~= 4MWh
5. Power to cruise at about 600mph ~= 1/4 power to take off = 22MW (waves hand)
6. Time available to cruise ~= 1hr
7. Distance cruised ~= 600miles
8. Electric 747 takes 600 people 600 miles = 360,000person/miles
Maybe the power to cruise is 1/2 of power to take off, they'd still get 120,000person/miles.