>Pathfinder 1 has a hybrid propulsion system, with two 150 kilowatt diesel generators working alongside 24 batteries to provide power for the electric motors

300KW is 1500 m2 solar panels at 200 W/m2 which given the airship's length of 120 m means 15m width - i.e. the airship can just be covered with those lightweight flexible solar panels (with 1500m2 of those solar panels weighting about the same as those 2 diesels and say 300 gallons of fuel) and be self-sustainable for unlimited flight time.