It’s a bit hard to restrict advertising like that in the US. In most case, about all you can do is to ask that they not make fraudulent claims, which is what Delta was doing.

The “sustainable aviation fuels” are things we know how to make, but they’re either very limited in supply (biofuels, where we’re burning a large chunk of the maize and soy crops already) or incredibly expensive (synthetic fuels from captured carbon marketed as ‘e-fuels’) The corporate research around these isn’t really designed to turn them into something which will get used at scale, but seems more like the PR exercises we’ve seen the fossil fuels industry repeatedly conduct in the past.

The batteries are coming, at least for short-haul flights. The factory to make the first ones with a high enough energy density to support commercial flights is being built as we type.