UA 273 then UA 3917 at Houston
Santa Ana → Houston → Austin
Timetable, Houston time
13:20UA 273 from Santa Ana at the gate
07:30UA 3917 to Austin leaves the gate
18 h 10 apart on the timetable, overnight
UA 3917 leaves 18 h 10 after UA 273 arrives on the timetable: more than half a day, so not a connection we count.