Table 2
Air: 2000 Data (unless noted)
Airports
"5,317 public-use airports"
"13,964 private-use airports"
Airports serving large certificated carriers1 
"29 large hubs (72 airports), 479 million enplaned passengers"
"31 medium hubs (53 airports), 102 million enplaned passengers"
"54 small hubs (69 airports), 40 million enplaned passengers"
"585 nonhubs (610 airports), 18 million enplaned passengers "
Aircraft
"8,228 certificated air carrier aircraft,2 5.4 billion domestic miles flown2 "
"219,464 active general aviation aircraft3 (1999), 3.9 billion statute-miles flown4 (1997)"
Passenger and freight companies5
75 carriers
616 million domestic revenue passenger enplanements
14.8 billion domestic ton-miles of freight
Certificated air carriers (domestic and international)
"Majors: 14 carriers, 672,000 employees, 590 million revenue passenger enplanements"
"Nationals: 32 carriers, 56,000 employees, 80 million revenue passenger enplanements "
" Regionals: 29 carriers, 3,600 employees, 6 million revenue passenger enplanements"
"1 U.S. Department of Transportation, Bureau of Transportation Statistics, Office of Airline Information, Airport Activity Statistics of Certificated Air Carriers, 12 Months Ending December 31, 2000 (Washington, DC: 2001)."
"2 Aerospace Industries Association, Aerospace Facts and Figures (Washington, DC: 2000/2001). "
"3 U.S. Department of Transportation, Federal Aviation Administration, General Aviation and Air Taxi Activity and Avionics Survey, Calendar Year 1999 (Washington, DC: 2001)."
"4 U.S. Department of Transportation, Federal Aviation Administration, General Aviation and Air Taxi Activity and Avionics Survey, Calendar Year 1997, FAA-APO-99-4 (Washington, DC: 1999)."
"5 U.S. Department of Transportation, Bureau of Transportation Statistics, Office of Airline Information, Air Carrier Traffic Statistics (Washington, DC: 2000)."
"SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics, National Transportation Statistics 2001, available at http://www.bts.gov."