Airship

An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air.
In early dirigibles, the lifting gas used was hydrogen, due to its high lifting capacity and ready availability. Helium gas is not flammable, unlike hydrogen, but is rare and relatively expensive. Significant amounts were first discovered in the United States and... meer