St. Louis Downtown Airport (IATA: CPS, ICAO: KCPS, FAA LID: CPS) is a public-use airport located in Greater St. Louis, one mile (2 km) east of the central business district of Cahokia Heights (formerly Cahokia), in St. Clair County, Illinois, United States. It is owned by the Bi-State Development Agency. The airport is located less than 3 miles from the Gateway Arch riverfront in St. Louis and is used by many business aircraft visiting the St. Louis region. Airport services include one full-service 24-hour fixed-base operator, an instrument landing system, an FAA air traffic control tower, and its own dedicated Index B aircraft rescue and firefighting (ARFF) service. It is utilized mainly by Saint Louis University's Parks College of Engineering, Aviation and Technology for training purposes, as well as the St.