Let's go back to the example of the 747. Most variants of this plane have a fuel capacity somewhere around 200,000 liters, which is really a lot of fuel. With a density of about 0.8 kilogram per liter, this gives it a fuel mass of 160,000 kilograms. The specific energy of jet fuel is around 12,600 watt-hours per kilogram. This means that with 1 kilogram of fuel, you could get a power of 1 watt for 1 hour—assuming you can use all of the energy, which you can't.
Now suppose I take all that jet fuel and replace it with batteries. Assume that I can replace the jet engines with equivalent electric-powered turbofan engines or something. So, that's a 160,000-kilogram battery. Electric cars use a lithium-ion battery, and the best specific energy you can get is about 250 watt-hours per kilogram. Now you can already see the problem. If I assume an electric motor is 50 percent efficient, our electric-powered 747 could fly for 22.
Would it help to have a smaller aircraft like the Cessna 172? Of course, it uses less power, but it also carries less fuel—just about 170 kilograms. If we replace that fuel with a lithium-ion battery, it could fly for about 30 minutes. That's still not great. If you reduce the speed from 220 km/hr to 150 km/hr, you can get a flight time of about 42 minutes, but you won't really be able to get a better distance, since you are flying slower.
Interesting answer but no reference to Venturi effect or Bernoulli principle in the explaination of lift?
It was an interesting article, would have been fun to include Hydrogen powered engins as well
2 miles ?
Aircraft refueller here. Great article! But have to point out that jet fuel (kerosene) isn't just for jets; it's specifically for turbine engines, used in many propeller planes. Conversely, piston engines use aviation gasoline (Avgas).