Airline reservation systems originated in the mid-1950s as relatively unsophisticated internal systems to help with tasks such as seat assignments, maintenance scheduling, and aircraft loading. Modern airline reservation systems are multi-faceted, full-service systems that assist with a variety of airline management tasks and service customer needs from the time of initial reservation through completion of the flightAmerican Airlines, an early pioneer in the use of commercial computer technology, developed a semi-automated customer reservation system called Reservisor by 1960. It required considerable manual intervention and had a reservation error rate of eight percent, which was the lowest in the industry at the time. Recognizing that semi-automatic systems would not be capable of handling the rapidly increasing demand for air travel, American Airlines had already begun working with IBM, in the late 1950s, to develop the first automated, online, real-time computerized reservation system (CRS). The joint project would use interactive, real-time computing technology developed for a U.S. government air defense project referred to as Semi-Automatic Ground Environment (SAGE).