Thayer Memorial Airport (ICAO: K42M) is a small public-use general aviation airport located in Thayer, Missouri, in the southern part of the state near the Arkansas border. It serves private pilots, small aircraft operators, and local aviation needs in Oregon County and the surrounding Ozarks region. The airport does not offer scheduled commercial airline service and is used primarily for personal, recreational, and light business aviation. It is one of many rural general aviation facilities maintained to support connectivity in remote areas of Missouri.