One of the more interesting earlier designs (from 1784) never built was an elliptical airship around 260 feet long that required 80 men to operate the three hand-cranked propellers. Giffard was ...

The massive blue-and-yellow airship floats ... when French engineer Henri Giffard filled a 144-foot-long bag with hydrogen. Using a steam engine to turn a large propeller, his invention lifted ...