the fuel is liquid sodium metal, an inexpensive and widely available commodity.

How very stupid we all have been during the last 200 years! /s

We don’t use this “inexpensive and widely available” fuel for making a campfire, or heating a house, or driving a car.

Producing enough sodium metal to enable widespread, full-scale global implementation of this technology should be practical, since the material has been produced at large scale before.

What a bullshit again.

Let us get smarter by looking at the whole cycle of energy:

Sodium metal is used as a carrier of energy in this idea. First we would need to invest energy to create the “fuel”, and later we can use the energy from it.

Now the problem gets obvious: It is not an even balance.

"There’s this natural cascade of reactions that happens when you start with sodium metal,” Chiang says. “It’s all spontaneous. We don’t have to do anything to make it happen

These reactions can only be so spontaneus because there is still a whole lot of energy stored in the sodium hydroxide etc. And this energy was needed in the beginning, on the way from sodium chloride to sodium metal, but later it can not be used completely for that airplane. A good part of it is wasted afterwards.

IMHO This “gap” in the cycle makes the whole idea much less useful than this guy is telling us.