How's this sound... since Austin and San Antonio are less than 100 miles apart, how 'bout one day in San Antonio and one day in Austin?
For those who want to rack up miles either on Delta or United, Delta has one of the shortest flights in their schedule: SAT-AUS (two flights daily). No connections, no fuss, no muss. It's only a 15-minute positioning flight for their SLC-SAT-AUS-SLC rotation, but what the hey!