Columbia is also known for its MKT Trail, a spur of the Katy Trail State Park, which allows foot and bike traffic across the city, and, conceivably, the state. It consists of a soft gravel surface for running and biking. Columbia also is preparing to embark on construction of several new bike paths and street bike lanes thanks to a $25 million grant from the federal government. The city is also served by American Airlines and United Airlines at the Columbia Regional Airport, the only commercial airport in mid-Missouri.