The civil airline industry is entirely privately owned and has been largely deregulated since 1978 , while most major airports are publicly owned . The three largest airlines in the world by passengers carried are U.S.-based ; American Airlines is number one after its 2013 acquisition by US Airways . Of the world 's 50 busiest passenger airports , 16 are in the United States , including the busiest , Hartsfield – Jackson Atlanta International Airport , the fourth-busiest Los Angeles International Airport , and the sixth-busiest O'Hare International Airport in Chicago . In the aftermath of the 9/11 attacks of 2001 , the Transportation Security Administration was created to police airports and commercial airliners
9/11 attacks
September 11 attacks
United States