As of January 2001, there were 19,306 airports1 in the United States, with 5,314 of these open to the public and known as public-use airports. The Federal Aviation Administration includes 3,364 of the existing public-use airports in its National Plan of Integrated Airport Systems (NPIAS). The NPIAS includes both commercial and general aviation airports that are eligible to receive grants under the Air Improvement Program. Commercial service airports are defined as public airports receiving scheduled passenger service with at least 2,500 enplaned passengers per year. These airports handle the vast majority of enplanements in the United States. In 2001, there were 546 commercial service airports. FAA estimates that 67 percent of the U.S. population lives within 20 miles of at least 1 of these airports.
U.S. Department of Transportation, Federal Aviation Administration, National Plan of Integrated Airport Systems (NPIAS) (2001–2005) (Washington, DC: 2002).
1 Includes civil and joint-use civil-military airports, heliports, STOL (short takeoff and landing) ports, and seaplane bases in the United States and its territories.