UA 2168 then DL 2709 at Houston
San Francisco → Houston → Atlanta
Timetable, Houston time
10:49UA 2168 from San Francisco at the gate
08:05DL 2709 to Atlanta leaves the gate
21 h 16 apart on the timetable, overnight
DL 2709 leaves 21 h 16 after UA 2168 arrives on the timetable: more than half a day, so not a connection we count.