One of seven American cities classified as Gamma world cities, Atlanta ranks third in the number of Fortune 500 companies headquartered within city boundaries, behind New York City and Houston. Several major national and international companies are headquartered in Atlanta or its nearby suburbs, including four Fortune 100 companies The Coca‐Cola Company, Home Depot, and United Parcel Service in adjacent Sandy Springs. The headquarters of AT&T Mobility (formerly Cingular Wireless, the largest mobile phone service provider in the United States, and Newell Rubbermaid are also in Atlanta and around the metro area, as well as other major companies Including Arby's, Chick‐Fil‐A, EarthLink, Equifax, Georgia‐Pacific, Oxford Industries, Southern Company, SunTrust Banks, and Waffle House. Over 75 percent of the Fortune 1000 companies have a presence in the Atlanta area, and the region hosts offices of about 1,250 multinational corporations. Delta Air Lines is the city's largest employer and the metro area's third largest. Delta operates the world's largest airline hub at Hartsfield‐Jackson Atlanta International Airport and, together with the hub of competing carrier AirTran Airways, has helped make Hartsfield‐Jackson the world's busiest airport, both in terms of passenger traffic and aircraft operations. The airport, since its construction in the s, has served as a key engine of Atlanta's economic growth.
