>>1733729afaik anything with less than 130 kilo starting weight doesn't need to be certified in the united states of freedom and can be flown without certification
even if only baloons ae certified you can combine them with a paramotor that again needs no licensing
think of clustered balooining with an enclosing hull and a propeller on your back
another possibility could be seperating the controls into a remote control unit and registering it as an uav could work in some places
then you could also make it float and drive out 12 miles to the sea at water level and be free from all requirements if you fly no flag
germany offers a licence but the requirements are too high for a hobby (if you start to work full time at an airship company that would be different)
a nice documentary containing hobby and mini airships
https://www.youtube.com/watch?v=_GCGRlRpvwkthat should be enough for most amateur builds
smaller countries will probably not have a airship license category as there are only a handfull and airships could be included in the balloons category if you get a flag of convenience