UA 574 then AA 1594 at Phoenix
San Diego → Phoenix → Austin
Timetable, Phoenix time
19:31UA 574 from San Diego at the gate
13:58AA 1594 to Austin leaves the gate
18 h 27 apart on the timetable, overnight
AA 1594 leaves 18 h 27 after UA 574 arrives on the timetable: more than half a day, so not a connection we count.