Airship

An airship is usually a flying structure used to transport goods, people, or may be used for war purposes, for example, the Skybreaker Alliance airship, which patrols the skies above Icecrown Citadel. It is usually used to refer to an Alliance flying machine, or the Alliance equal to a Horde Zeppelin.

Goblin zeppelins are also called airships.

The Icecrown gunships are sometimes called airships on the official community site and in several spells and files. The 'gunships' above the Isle of Conquest are called Airships in-game, showing it is an alternate name.

The World of Warcraft Battle Chest Guide refers to zeppelins as airships at times.

In-game
In-game, airships are used for many different things such as transportation of people, materials and warlike use, as seen in Icecrown.