The airline was established on March 15, 1967 by Herb Kelleher as Air Southwest Co. and adopted its current name, Southwest Airlines Co., in 1971, when it began operating as an intrastate airline wholly within the state of Texas, first flying between Dallas, Houston and San Antonio. The airline has more than 60,000 employees and operates about 4,000 departures a day during peak travel season.

As of 2018, Southwest carried the most domestic passengers of any United States airline. The airline has scheduled services to 103 destinations in the United States and ten additional countries.

Herbert Kelleher and Rollin King

Southwest Airlines was founded in 1966 by Herbert Kelleher and Rollin King, and in 1967 it was incorporated as Air Southwest Co. Three other airlines took legal action to try to prevent the company from its planned strategy of undercutting their prices by flying only within Texas and thus being exempt from various regulations. The lawsuits were resolved in 1970, and in 1971 the airline began operating regularly scheduled flights between Dallas Love Field and Houston and between Love Field and San Antonio, and adopted the name Southwest Airlines Co. In 1975, Southwest began operating flights to various additional cities within Texas, and in 1979 it began flying to adjacent states. Service to the East and the Southeast started in the 1990s.

To date, Southwest schedules flights to 103 destinations in 40 states (and Puerto Rico), Mexico, Central America and the Caribbean. Southwest does not use the hub and spoke system of other major airlines, preferring the point-to-point system, combined with a rolling hub model in its base cities.

According to wikipedia