Bring back hydrogen lifting gas
TLDR:<p>> With modern engineering standards, there is no doubt that hydrogen could be made a safe lifting gas.<p>Disadvantages of hydrogen:<p>* burns (but only with sufficient oxygen, eg a mixture of air and 4% up to 75% hydrogen)<p>Advantages of hydrogen:<p>* lifts 8% more than helium (per volume). Not a huge difference, but not trivial for an airship<p>* costs 98.5% less than helium (!) (Airships have crashed because helium was too expensive to vent: safety valves on the <i>USS Shenandoah</i> were capped, 14 crew members lost their lives.)<p>> Airships are too slow for human travel<p>Too slow for transportation, maybe. But leisure travel? Imagine a one week air safari from Kilimandjaro and the Serengeti to Kruger Park. It could be awesome.<p>Edit to add:<p>(Leisure air travel/Safari is my own pipe dream. The article suggests cargo):<p>> If airships were to make a major comeback, it would be in cargo service.<p>> Cargo airships would need to be big—bigger than the Hindenburg. [...] ”’the lift-to-drag ratio, a critical parameter in aircraft performance, gets better as the airship gets bigger)<p>> Ginormous airships require a lot of lifting gas—perhaps a million cubic meters<p>> FAA has discouraged the return of the airship in the use case that makes the most sense