It's true that energy density of batteries is a lot lower than gasoline, but electric motors are a lot more efficient. It doesn't make up the whole difference, but it does make up some of it. Also, battery technology is improving pretty rapidly.

Electric aviation is not yet viable commercially, but it will be soon. I'm working at a company building electric aircraft, and one of our prototypes has done a flight of more than 380 miles. Note that this is a prototype, in ideal conditions, with a tailwind, last few miles were circling the airport within the glide cone, etc. The actual production vehicle range, with all of the safety margins, seats for passengers, passenger weight, etc, will be a lot less; but still, 150 miles is enough for many commercially viable trips, especially in dense areas like the BosWash corridor, or getting from suburbs to a long haul airport, or many others.

Electrification can also make viable new architectures, like VTOL, and the extra efficiency and longer maintenance intervals can drastically drive down operating costs; so there will be many trips that are economically viable in an eVTOL that wouldn't be in conventional airplanes (due to needing an airport) or helicopter (due to high fuel and maintenance costs).