When men designed airships in the 1830ís, their goal was to be able to travel longer distances than simple hot air balloons, as well as the ability to steer their aircraft using engines. That entailed a massive tank of highly explosive hydrogen.
Several technical advances changed the airships until a first important flight in 1900 with the first rigid airships. Between 1900 and 1930, airship was used to assert the national prestige of big nations. The high flammability of hydrogen led however to several disasters. The English gave up using hydrogen in 1930. Germans went on their exploitation of commercial hydrogen-powered airships until the famous disaster of May 6, 1937 near New York City, which resulted in 35 deaths among the 97 passengers. The truth is deadlier disasters occurred, but no camera was there to shoot them!
Since 60 years, airships are using helium, a non-explosive gas.
Today, some airships like the P-791 are expecting to lift between 500 to 1000 tons.