The Lockheed F-104 Starfighter is a single-engine, high-performance, supersonic interceptor aircraft originally developed for the United States Air Force (USAF) by Lockheed. One of the Century Series of aircraft, it served with the USAF from 1958 until 1969, and continued with Air National Guard units until it was phased out in 1975. The National Aeronautics and Space Administration (NASA) flew a small mixed fleet of F-104 types in supersonic flight tests and spaceflight programs until they were retired in 1994. USAF F-104Cs saw service during the Vietnam War, and F-104A aircraft were deployed by Pakistan briefly during the Indo-Pakistani wars. Republic of China Air Force (Taiwan) F-104s also engaged the People's Liberation Army Air Force (China) over the disputed island of Quemoy. The ultimate production version of the basic fighter model F-104 was the F-104S all-weather interceptor designed by Aeritalia for the Italian Air Force, and equipped with radar-guided AIM-7 Sparrow missiles. An advanced F-104 with a high-mounted wing, known as the CL-1200 Lancer, did not proceed past the mock-up stage. A set of modifications produced the F-104G model, which won a NATO competition for a new fighter-bomber. Several two-seat trainer versions were also produced, the most numerous being the TF-104G. A total of 2,578 Starfighters were eventually produced, mostly by NATO members. The F-104 served with the air forces of over a dozen nations. The operational service of the Starfighter ended with its retirement by the Italian Air Force in May 2004, some 46 years after its introduction in 1958 by the USAF.