Hindenberg was full of flammable hydrogen. Helium is not flammable. No crewed or uncrewed airship in service today uses hydrogen for buoyancy - FAA regulations prohibit it.
884283: a 747-400 cruises at just shy of Mach 1 (actually 0.855, or 920km/h/570mph) at 35,000 feet (10700m). LTOL (Laden Takeoff/Landing) speed is 250kt. That's shy of 290mph. 80kt=92mph. Not legal anywhere really apart from the German Autobahn and certified race tracks (most places in the US are limited to 55mph and the UK has a (laughable) limit if 70. I say laughable because it's less a limit, more a goal - most roads you'll be lucky if you hit 40).