An air balloon is a flexible bag filled with a type of gas, such as helium, hydrogen, nitrous oxide or air. Modern balloons can be made from materials such as rubber, latex, polychloroprene or a nylon fabric, while some early balloons were sometimes made of dried animal bladders. Some balloons are purely decorative, while others are used for specific purposes such as meteorology, medical treatment, military defense, or transportation. A balloon's properties, including its low density and relatively low cost, have led to a wide range of applications.

"Indians of Central and South America made balls of leather much as we make balloons today" (Reader's Digest). In 1643 Evangelista Torricelli, an Italian physicist, showed air was something more than nothing. The Chinese, Japanese and Native American cultures led to beginning of the balloon.

The first balloon was (called the balloon of pie) invented by Brazilian-born Portuguese priest, Bartolommeo de Gusmão, and the first public exhibition was to the Portuguese Court on August 8, 1709, in the hall of the Casa da India in Lisbon. The rubber balloon was invented by Michael Faraday in 1824; it was inflated with hydrogen and used in his experiments with that element. Rubber balloons were soon after sold for a penny a piece in parks and circuses in America. The more familiar latex balloons of today were first manufactured in London, 1847, by J.G. Ingram, but mass production did not occur until the 1930s. According to the Reader's Digest, children and adults send up a billion balloons each year in celebration.