Is there anything there that would not have been true 50 years ago? What's changed about airships that makes them practical now, when (presumably) they weren't before?
Climate change and the need to get rid of fossil fuels as the base for transportation. With cheap oil, planes and helicopters are superior in most cases.
But when you cover a airship with lightweight solar foil and power it electrical, you could get transportation for allmost free (in sunny areas). But even without that, they fly way more economic, since you get the uplift for free. (starting of a plane and reaching height, consumes the most fuel)
