Beginning in 1908 and lasting until 1937, the U.S. Army established a program to operate airships. With the exceptions of the Italian-built Roma and the Goodyear RS-1, which were both semi-rigid, all Army airships were non-rigid blimps. These airships were used primarily for search and patrol operations in support of coastal fortifications and border patrol. During the 1920s, the Army operated many more blimps than the U.S. Navy. They were also used because they were not seen as "threats" on the battlefield by opposing forces, unlike airplanes, due to their passive role in combat. History The history of American military aviation began during the Civil War, when the Union Army operated observation balloons. Later, a balloon was used by the US Army in Cuba during the Spanish–American War. These were ad hoc and not part of an established branch of the Army. The use of observation balloons continued after the end of World War I. The last use of observation balloons by the Army was during maneuvers conducted in Louisiana during September 1941. Balloons must either be tethered, or go where they are blown by the wind, but towards the end of the nineteenth century powered airships, capable of being directed at the will of the pilot, were developed. In 1908, the US Army experimented with its first powered aircraft, the SC-1, or Signal Corps number 1. It was a small non-rigid airship with a top speed under 20 mph and an endurance of just over 2 hours. Following tests at Fort Myer, the SC-1 was sent to Fort Omaha, Nebraska, where the Signal Corps School was located. While the SC-1 was being tested at Fort Myer, the Signal Corps had built an airship hangar and a plant to produce hydrogen gas at Fort Omaha. Fort Omaha became, for a while, the first permanent military airfield in the United States. The SC-1 was scrapped in 1912, and the base at Fort Omaha closed in 1913. World War I The US Army operated French observation balloons during World War I, but did not operate another airship until after the war ended. During World War I the Joint Airship Board assigned the US Navy the role of acquiring and developing rigid airships. This did not dissuade the Army from pursuing its own course. Colonel William Hensley flew as an observer on the return voyage of the British R34 airship from Long Island,