Airships are full of a gas that is lighter or less dense than the surrounding air. That is how they generate lift. They may do this by heating the gas in their envelope (hotter air is less dense) or by using a gas that is naturally less dense than oxygen, such as helium or hydrogen. However, there are downsides to these gases – helium is relative rare (or was at the time airships were first used in our own world) and hydrogen is highly flammable (leading to airship explosions and disasters). The type of gas used in the airships of a fictional world may be an opportunity to insert a fictional material.

An airship envelope is where its’ gas is contained. A single envelope may hold multiple individual cells of gas. This ensures that if one cell ruptures there are others still intact to provide lift. Gondolas are where the crew and any passengers of the airship reside. Gondolas may be directly attached to the envelope (such as with zeppelins) or hang beneath it (such as with hot air balloons).

Aerostats are aircraft that float in the air using a buoyant gas (blimps, zeppelins, etc.) while an aerodyne is an aircraft that uses movement to generate lift (airplanes, helicopters, etc.).

Zeppelins take their name from Count Ferdinand von Zeppelin, who founded the company that first produced this new type of rigid airship.