> But for all their high-tech advances, Hunt said, the new airships would still get their buoyancy from hydrogen, a highly flammable gas that is 14 times lighter than air. It’s the same gas the Hindenburg and the other big zeppelins used in the 1930s.
As a reminder, the Hindenburg was originally designed for helium. They were unable to get the US to lift its ban on the export of helium under the Helium Control Act of 1927.
> As an additional bonus, Hunt said, the fuel cell would generate as a byproduct water that could be released as the craft passed over regions hit by drought.
That's isn't much amount of water, and certainly not enough to affect a drought.
Figuring 2km long x 200m x 200m that's about 3E9 mol of gas. You need some lifting gas for the vehicle weight - call it 1E9 mol or 5E8 mol of water, which is 30K tons. That's 27 acre feet, which appears to be enough for about 15 acres of potatoes for a growing season, using numbers from https://www.ardentmills.com/media/1725/colorado-quinoa-susta... .
And I think I'm highly over-estimating.