An airship is a large aircraft that floats through the sky using a giant balloon filled with a gas that's lighter than air, typically helium. Unlike airplanes, which need engines and wings to stay aloft, an airship rises naturally because the gas inside weighs less than the air around it, the same way a helium balloon floats up at a birthday party.

The most famous airships were called dirigibles or zeppelins. These massive flying machines had rigid frames covered in fabric, with passenger cabins hanging underneath. In the 1920s and 1930s, airships carried passengers across oceans in luxury, floating smoothly through the clouds. The German Hindenburg was the largest airship ever built, stretching longer than two football fields.

Airships mostly disappeared after the Hindenburg caught fire in 1937, but modern airships still exist. You might see small ones called blimps floating above sports stadiums with advertising on their sides. Unlike rigid airships, blimps have no internal framework. They maintain their shape purely from the gas pressure inside, like an inflated beach ball.

Today, engineers are reimagining airships for cargo transport, since they can carry heavy loads while using far less fuel than airplanes or trucks.