> We fly in aluminum balloons filled with jet fuel all the time.
Hydrogen ignites significantly more readily than jet fuel does, and protecting the gigantic volume of an airship's envelope (which is multiple times that of the payload) is a lot harder than protecting a plane's fuel tanks.
Not to mention the airship still need fuel tanks to move around, it's not a captive balloon.
Take a look again at the video I linked to and try and explain how jet fuel doesn't really catch fire and isn't much of a problem if it does.
Preventing an onboard fire is probably the #1 concern of jet designers.
Experience has gotten them pretty good at it. Damned good. Amazingly good. But never forget that jet fuel is not safe. It burns. It burns hot. It'll melt everything on an airplane it touches. It'll burn your wing off in seconds. The whole point of jet fuel is it stores a LOT of energy in a very small amount of weight.
Airlines have gotten amazing good at evacuations, such that I am surprised how well the general public is at them in emergencies.
Look at pictures of any crash where everyone (or almost everyone) survived and the fire damage to the plane is frankly astonishing.
Hydrogen zeppelins could be designed to nearly perfectly mitigate all fire risk; the real danger is weather related. (Ideas such as hydrogen can’t burn if oxygen isn’t present, fireproof bags, gondola suspended below so fire can’t reach it, emergency evacuation planning for when it does hit the ground, capability of venting, fire suppressions, etc).
Hydrogen ignites significantly more readily than jet fuel does, and protecting the gigantic volume of an airship's envelope (which is multiple times that of the payload) is a lot harder than protecting a plane's fuel tanks.
Not to mention the airship still need fuel tanks to move around, it's not a captive balloon.