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.

Taken over by the United States Army Air Forces on 1 August 1939 as a basic (level 1) pilot training airfield.

Flying training was performed with Fairchild PT-19s as the primary trainer with also several PT-17 Stearmans and a few P-40 Warhawks assigned.

The military airfield was inactivated 12 March 1944 with the drawdown of AAFTC's pilot training program.

This article incorporates public domain material from the Air Force Historical Research Agency