UA 4989 then DL 2709 at Houston
Mobile → Houston → Atlanta
Timetable, Houston time
10:50UA 4989 from Mobile at the gate
08:05DL 2709 to Atlanta leaves the gate
21 h 15 apart on the timetable, overnight
DL 2709 leaves 21 h 15 after UA 4989 arrives on the timetable: more than half a day, so not a connection we count.