Amendments to the act in the 1960s increased the size of the commission from three to six commissioners and broadened its role to include, among other things, acquiring land for airports and the economic regulation of intrastate airlines operating within Texas.
In doing so, and taking certain other steps to minimize its participation in interstate commerce, it escaped then-tight Federal economic regulation.
There then followed two-to-three years of legal challenges to that decision, with Federally-regulated airlines flying within Texas determined to stop Southwest before it started.
[2] Under TAC economic oversight, Southwest successfully started operations in 1971 and expanded across Texas by 1978, from Harlingen in the south to El Paso in the west, growing from three aircraft to 13.
By that time Southwest had come to dominate intra-Texas air travel, having dropped fares significantly and stimulated markets substantially.