They are hulking, but graceful — human-made whales that float in the air. For over a century, lighter-than-air vehicles have captured the public imagination, playing a recurring role in our visions of alternate realities and futures that might have been. In these visions, cargo and passengers traverse the globe in smoothly gliding aircraft, then dock elegantly at the mooring towers on top of Art Deco skyscrapers.
In real life, perhaps the most familiar craft of this type is the blimp emblazoned with the Goodyear logo. But a blimp is a non-rigid airship, meaning: there’s no structure inside the balloon. Rather, the shape is maintained by the pressure of the lifting gas inside. A little cockpit, engines, and rudder were attached to the outside. Today, blimps are mostly just PR gimmicks, lighter-than-air crafts have been seriously considered as the perfect design solution for all kinds of problems over the years, at least in theory. And despite setbacks and failures, some people still haven’t given up on the promise of airships. [...]