I'm aware of the existence of the Wright Amendment, even though I've never been to Texas. (But I do know others who have been there, though) I figure that this law was put in place, like Desertjets said, to keep as little traffic as possible from being siphoned off to Love Field, which sits right in the middle of Dallas. But there may be opposition to the repealing of the Wright Amendment, not just by AA and DFW, but also by residents of Dallas who live under the flight approach paths into Love Field.
Last I heard, there's a court fight about changing the Wright Amendment to allow flights out of Love Field to more states.
I can understand the situation at Love Field, as Edmonton Municipal(YXD), now City Centre Airport, had similar restrictions placed upon it by Transport Canada, (a Canadian gov't department). The airport, like Love Field sits near downtown Dallas, sits only a few miles from downtown Edmonton. Flights were restricted at first to Northern Alberta, Calgary, the province of Saskatchewan to the east and the Northwest Territories to the north. Then about three years before it was closed to scheduled service in 1996 to planes greater than 10 seats and the major regional carriers were shifted to Edmonton International(YEG), the law was changed to allow jet a/c flights into BC, including Vancouver and Victoria. I believe this law was in place to keep too much traffic from being siphoned out of YEG, and likely to keep aircraft noise to a minimum. I live right underneath one of YXD's flight approach paths, so I remember how loud and nasty the 737s and the F28s were going right over my apartment. Edmonton is a city of 670,000(city), so you can imagine how many people would feel about a/c noise in their backyards!
I've got a question that hopefully you Texans can answer: Does the Wright Amendment affect other airports within the Dallas-Fort Worth Metroplex besides Love Field?