From most publications and individuals with a platform from which to comment on such things, the coverage is breathlessly positive, merely reprints of glossy press releases in an impressive show of “suspension of common sense.”

Do electric airplanes fly? Well, of course they do! We’ve known that since the early 1970s. Spin a propeller fast enough, even if you use a giant rubber band to do it, and you’ll create enough thrust to get a light plane off the ground. The fatal flaw, that single thing standing in the way of effective use of electric-powered aircraft, is very well understood and easily summed up in two words—“energy density.’’ //

The amount of energy that can be stored and released on demand, be it in a battery or avgas or a twisted rubber band, per unit of mass is known as specific energy.

Es = E/m, that is, specific energy=kilowatt hours/pounds.

What this means is, the higher the specific energy, the more energy you will get out of a pound of whatever it is you’re storing it in. This is the “fatal flaw” I mentioned earlier. The specific energy of 100LL avgas is about 47, while the best lithium-ion battery around is about 1. Put another way, 10 pounds of battery will store 1,200 watt/hours of energy while 10 pounds (1.66 gallons) of 100LL contains 48,000 watt/hours. No clue on the rubber band. //

From a practical perspective, avgas gives you options. If you need to carry a fourth passenger in a 172, merely reduce the fuel load. Need to do that in an electric 172? Ah, no. ///

A gas turbine generator using just one of the two engines on a 737 puts out 30+MW.

I don't think that an airplane like the 737 can carry 100MWh of energy in batteries and still have usable payload.