The Wright Amendment of 1979 is a federal law that governs traffic at Dallas Love Field, the pre-1974 airport in Dallas. It originally limited most nonstop flights to destinations within Texas and neighboring states. The limits began to phase out in 1997 and 2005; in 2006, the amendment was repealed, with some restrictions intact until 2014, but added a restriction on the number of gates allowed.
When airline deregulation came in 1978, Southwest began to plan interstate flights from Love Field, causing groups affiliated with Dallas/Fort Worth International Airport, including the city of Fort Worth, Texas, to push the Wright Amendment through Congress to restrict such flights. Under the amendment, Southwest and other airlines were barred from operating or even ticketing passengers on flights from Love Field to destinations beyond the states that border Texas. The Wright Amendment’s restrictions did not apply to aircraft with 56 or fewer seats; Southwest did not use the 56 seat loophole. Southwest's first schedule out of Texas was Hobby to New Orleans about February 1979.
In 1997 Southwest’s efforts paid off with the Shelby Amendment, which added Alabama, Mississippi and Kansas to the allowed destinations. Southwest began nonstop service between Dallas Love Field and Birmingham, Alabama.
Southwest just flew to DAL, HOU and SAT until 1975 when it added Harlingen. In 1979 it flew to eleven Texas cities and added its first route out of the state, Houston-New Orleans, around the end of the year. In 1981 it expanded north to Tulsa and Oklahoma City and west to Albuquerque; in 1982, north to Kansas City and west to Phoenix, Las Vegas and California.
Flights to Denver started in 1983 (and ended in 1986), to Little Rock 1984, to St Louis and Chicago Midway in 1985, to Nashville in 1986 and to Detroit Metro and Birmingham in 1987. Eastward expansion resumed in 1992 with Cleveland and Columbus, then Baltimore in 1993. The Pacific Northwest started in 1994 after the Morris Air takeover; Tampa and Fort Lauderdale started in January 1996. East to Providence in 1997, Manchester in 1998, and Islip and Raleigh-Durham in 1999.
Southwest's only route within California was San Francisco-San Diego until it started Oakland in 1989; in the next few years its capacity on the West Coast ballooned.