Airships are kind of aircraft. Airships float in the sky and do not have to move to stay up. This is different from aeroplanes that stay up in the sky by moving. An airship floats like a balloon. But an airship is different from a balloon. An airship has an engine for power and a way to control its direction of movement. A balloon does not have an engine or a way to control its direction of movement. Kinds of airshipsEditThere are three kinds of airships. The difference is the amount of structure in the airship.- Rigid airships - Rigid airships have big structures in them. The biggest airships were rigid airships, made in the 1920s and 1930s. Big rigid airships were also called dirigibles.- Semi-rigid airships - Semi-rigid airships have small structures in them. There are only a few semi-rigid airships.- Non-rigid airships - Non-rigid airships have no structures in them. Non-rigid airships are also called blimps. Most airships are non-rigid airships. Blimps were used by the United States in WWII to fight against submarines. Blimps are now used mostly for advertising and sometimes for looking down, for example at sport stadiums and tourist attractions. The most famous airship was the Hindenburg. The Hindenburg was a rigid airship made by the Zeppelin airship company. It burned when it was landing on May 6, 1937. There were 97 people on the airship when the fire started. The fire killed 35 of these people and one person on the ground.