Milwaukee Mitchell International Airport (MKE) traces its origins to October 5, 1926, when the Milwaukee County Board of Supervisors approved the $150,000 purchase of Hamilton Airport, a private airfield owned by local aviator and entrepreneur Thomas Hamilton. The first terminal was a converted farmhouse, the Hirschbuehl farmhouse, which opened in the summer of 1927. Commercial air service followed quickly: Northwest Airways began flights from Milwaukee to Chicago and the Twin Cities in July 1927. In 1941, the airport was renamed Billy Mitchell Field in honor of Milwaukee-raised Brigadier General William "Billy" Mitchell, an outspoken advocate for military air power who is widely regarded as a father of the U.S. Air Force. The current passenger terminal opened in 1955. The airport was renamed General Mitchell International Airport in 1986, then rechristened Milwaukee Mitchell International Airport in February 2019 to more directly anchor it to the city and region it serves.

About 5 miles south of downtown Milwaukee, MKE has an unusually broad catchment area. It is often described as Chicago's third airport, drawing travelers from the northern Chicago suburbs who choose it over O'Hare or Midway. It also serves as the primary diversion airport for O'Hare. An Amtrak station opened on the airport's western edge on January 18, 2005, making MKE one of only 4 airports in the country at the time to offer direct Amtrak rail access, with shuttle service connecting the platforms to the terminal. The FAA classifies MKE as a medium-hub commercial facility.

The airport operates a single terminal with 2 active concourses, C and D, and 5 runways, the longest stretching approximately 9,990 feet. Carriers including Southwest, Delta, American, United, Alaska, and Frontier serve the airport, with nonstop routes reaching more than 40 cities. MKE carried nearly 5.9 million passengers in 2025, still rebuilding toward its pre-pandemic peak of nearly 6.9 million in 2019. The airport's quirky "Recombobulation Area" signs, installed in 2008 to help travelers reassemble after security screening, have become one of its most recognized cultural exports.