Dirigibles and Blimps.

Lighter-than-air craft include both dirigibles, with rigid hull structures, and blimps, with limp hull structures that fall flat when deflated. Blimps were used during both world wars, but they were too small to carry many bombs in wartime or many passengers in peacetime. The large dirigibles could perform either mission.

The Zeppelin.

The French invented the airship in the late eighteenth century, but the craft remained strictly experimental for a century until Graf Ferdinand von Zeppelin caused the Germans to move permanently into the forefront of the field. Indeed the word zeppelin became a generic term for the dirigible. Americans did little in the early period of experimenting with lighter-than-air craft, but when they saw the power of German zeppelins on bombing raids over England in World War I and watched while the huge craft soaked up anti-aircraft fire and then floated...