» This article is about balloons in general. See also Balloon (aircraft) and Toy balloon. A balloon is a flexible bag filled with a type of gas, such as helium, hydrogen, nitrous oxide or air. Early balloons were made of dried animal bladders. Modern balloons can be made from materials such as rubber, latex, polychloroprene or a nylon fabric. Some balloons are purely decorative, while others are used for specific purposes such as meteorology, medical treatment, military defense, or transportati… (More on Balloon)