Most home-built airships are non-rigid using envelope pressure to maintain their shape.  That’s because rigid airships normally have to be huge to support their gigantic frame.  Rigidity improves maneuverabilty and allows increased speed.  JP Aerospace has just designed 1.7 PSI thin-film airbeams light enough to construct into a small airship.  This bodes really well for autonomous and manned small airships.  Oh, if you don’t know JP Aerospace, they’re planning to float in to space.