James M. Cox Dayton International Airport (IATA: DAY, ICAO: KDAY), also referred to as simply Dayton International Airport, is a public airport located 9 miles (14 km) north of the city of Dayton in Montgomery County, Ohio, USA.

It was founded in 1936 when the city purchased the original private airstrips from a corporation. The airport is named after James M. Cox, a former governor of Ohio, Democratic presidential nominee, and publisher of the Dayton Daily News.

Dayton International Airport handled 1,446,673 passengers in 2004. The airport was a hub for Piedmont Airlines until its merger with USAir. After the merger, USAir continued to maintain Dayton as a hub for a short while before eliminating some of its "long" routes like those to Los Angeles, San Francisco, Dallas and to Floridian cities in preference to its Pittsburgh and Indianapolis hubs. USAir, and its successor US Airways, sustained Dayton as a Midwest focus-city with routes to cities like Grand Rapids, Indianapolis, and Columbus with routes to some other cities like Boston plus US Airways hubs in Pittsburgh, Charlotte, Philadelphia, New York and Washington D.C. The airport also served as a hub for Emery Worldwide, a freight carrier.