"using cheaper-than-plane airships"
Oopsie. Big boo-boo right there. The Zeppelin NT, with a passenger capacity of 12, costs about $20 million each. A Cessna 208B Grand Caravan EX, with a passenger capacity of 13, costs about $2 million.
The Zeppelin has a range of 900 km at 115 km/h on 447 kW. The Cessna, 1996 km at 343 km/h on 647 kW.
The $40 million Airlander 10 is not believed to have any passenger facilities at all. A developed production version due in 2018 is touted as having 19 seats.
Maintenance costs are enormous for airships and far outweigh the fuel costs. And they have to be tended all the time while parked on the ground.