The word “electric” is quite fashionable and has become synonymous with the future. People seem to think technology is evolving towards a day where everything, cars, planes, ships, will be electric.
But let’s hold on for a moment. One kilogram of oil has about 45 MJ of energy. One kilogram of current batteries has less than 1 MJ (and a theoretical limit of about 3 MJ). To be fair, we need to multiply by the engine efficiency, because something like 75% of oil energy is lost as heat when the engine produces movement. But still that makes oil more than 10 times more energy-packed than batteries (by mass—by volume it’s about 4 times more).
A fully loaded Boeing 777 weighs about 300 tons. Approximately half of those is the fuel. If we made it electric, in order for it to carry the same amount of energy, it would need to weigh more than 1700 tons. You guessed correctly: it would be unable to lift itself into the air.