The Citation I is an executive jet. The developer is the American company Cessna Aircraft Company. The prototype was the Cessna 500 Citation aircraft. After the release of this model, 5 years later, an upgraded version of the Citation I entered the market. It features an enlarged wing span, JT15D-1A engines. Production was discontinued in 1985. By this time, 691 aircraft have been sold. The aircraft was mainly used as a private and staff transport.