A few months later on November 21st, of that year, Pilatre de Rozier and marquis d'Arlandes made the first manned flight, also in a Montgolfier balloon. Balloons are large bags filled with a gas that is less dense, or lighter, than the air on the outside of the bag. The less dense gas rises, the same way a bubble of air does in water, carrying the bag with it. Balloons come in several designs. The typical round bag is used in sport and weather balloons.
Dirigible designs are long and sausage shaped.
Dirigibles are divided into airships with rigid frames, called zeppelins, and ones with no frame, called blimps. Unlike sport balloons most dirigibles have motors that allow the ship to sail where the pilot wishes, rather than just being guided by the wind. Hot air is used in most smaller sport balloons, but is unsuitable for larger airships where it cools too quickly. Instead helium or hydrogen gas is used. Helium and hydrogen are two gases which are lighter than air even at the same temperature as the air.