UA 2476 then DL 3876 at Denver
San Diego → Denver → Austin
Timetable, Denver time
12:10UA 2476 from San Diego at the gate
09:42DL 3876 to Austin leaves the gate
21 h 32 apart on the timetable, overnight
DL 3876 leaves 21 h 32 after UA 2476 arrives on the timetable: more than half a day, so not a connection we count.