Balloon (aeronautics) they are popular for balloonist sport activity. The first balloon which carried passengers used hot air to obtain buoyancy and was built by the brothers Josef and Etienne Montgolfier in Annonay, France in 1783: the first passenger flight was 19 September 1783, carrying a sheep, a duck, and a rooster. The first tethered manned balloon flight was by a larger Montgolfier balloon, probably on 15 October 1783. The first free balloon flight was by the same Montgolfier balloon on 21 November 1783. When heated, air expands, so a given volume of space contains less air. This makes it lighter and,
Organization of the Air Service of the American Expeditionary Force "observation wings" were created to coordinate the reconnaissance activities of the five corps air services. The basic units of the air service were the squadron for powered aircraft and the company for balloons. 45 squadrons (38 of which conducted combat operations) of aircraft and 17 companies of balloons served at the front. The 20 pursuit and seven bombardment squadrons were authorized 25 aircraft (including spares) and 18 crews each by the "Field Service Regulations", while the 18 observation squadrons were each authorized 24 planes and 18 crews. Balloon companies were equipped with one balloon and approximately six observers each. The