Baton Rouge Metropolitan Airport (IATA: BTR, ICAO: KBTR, FAA LID: BTR), also known as Ryan Field, is a public use airport located four miles (7 km) north of the central business district of Baton Rouge, a city in East Baton Rouge Parish, Louisiana, United States.

The airport was originally Harding Field during World War II and was used by the United States Army Air Forces Technical Service Command as a maintenance and supply base. Its uses also included training pilots to fly P-47 Thunderbolts. One of the Thunderbolt pilots trained at Harding was Quentin Aanenson, who survived the war, and in 2007 appeared in Ken Burns' The War, a PBS film about World War II. Training was dangerous, The War noting that "Five members of Aanenson's group of 40 trainees died before they got a chance to go overseas".

Many other aircraft were used at Harding, including P-40 Warhawks, P-39 Airacobras, A-36 Apaches, and B-26 Marauders.

Today, other than the runways, virtually no traces remain of the military installation.