Airship is a kind of lighter than air aircraft. The biggest difference between airship and hot air balloon is that it has the device to propel and control the flight state. The airship is composed of a large streamlined hull, a pod under the hull, a stern for stability control and a propulsion device.
The air bag of the hull is filled with buoyant gas (hydrogen or helium) which is less dense than air, so as to generate buoyancy and lift the airship. The pods are for people to ride and load cargo. The tail surface is used to control and maintain the stability of course and pitch. Large civil airships can also be used for transportation, entertainment, disaster relief, film and television shooting, scientific experiments and so on. For example, in the event of a natural disaster, if the communication is interrupted, a buoy can be quickly launched. By carrying the communication transponder through the buoy, the mobile communication recovery of the whole disaster area can be completed in a very short time.