A "Luftschiff," or airship, is a type of aircraft that is lighter than air. It uses gas, such as helium or hydrogen, to lift off the ground. Airships have a large envelope filled with this gas, and they are often used for advertising, tourism, and surveillance. The most famous type of Luftschiff is the Zeppelin, which was developed in the early 20th century. Unlike airplanes, airships can float gently through the air and can be steered with more precision. However, they are slower than airplanes and are less commonly used today.