UA 281 then DL 3876 at Denver
Houston → Denver → Austin
Timetable, Denver time
11:22UA 281 from Houston at the gate
09:42DL 3876 to Austin leaves the gate
22 h 20 apart on the timetable, overnight
DL 3876 leaves 22 h 20 after UA 281 arrives on the timetable: more than half a day, so not a connection we count.