Bring back hydrogen lifting gas
TLDR:> With modern engineering standards, there is no doubt that hydrogen could be made a safe lifting gas.Disadvantages of hydrogen:* burns (but only with sufficient oxygen, eg a mixture of air and 4% up to 75% hydrogen)Advantages of hydrogen:* lifts 8% more than helium (per volume). Not a huge difference, but not trivial for an airship* costs 98.5% less than helium (!) (Airships have crashed because helium was too expensive to vent: safety valves on the USS Shenandoah were capped, 14 crew members lost their lives.)> Airships are too slow for human travelToo 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.Edit to add:(Leisure air travel/Safari is my own pipe dream. The article suggests cargo):> If airships were to make a major comeback, it would be in cargo service.> 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)> Ginormous airships require a lot of lifting gas—perhaps a million cubic meters> FAA has discouraged the return of the airship in the use case that makes the most sense