Southwest Airlines has a long history with alcohol, and not simply because their long-time Chairman Herb Kelleher had a thing for Wild Turkey.
Prior to deregulation in 1978, the Civil Aeronautics Board was ‘experimenting with price competition’ and airlines were allowed to cut their Dallas – Houston fare to $13 and undercut Southwest (which as an intra-state airline wasn’t subject to the CAB’s price regulation). Southwest responded by offering two fares: a $13 matching fare, and their previous $26 fare with which they threw in a fifth of liquor (customer’s choice). Folks expensing their tickets bought the higher fare, and Southwest Airlines became the biggest liquor distributor in the state of Texas.