This is almost entirely about helium. There exist hot-air and hybrid airships that eliminate or lessen the need for helium. They haven't succeeded much yet for

This is almost entirely about helium. There exist hot-air and hybrid airships that eliminate or lessen the need for helium. They haven't succeeded much yet for other reasons, I guess. But cargo blimps sound very interesting. Maybe self-driving blimps will be more cost-effective.