UA 4878 then DL 2709 at Houston
Mobile → Houston → Atlanta
Timetable, Houston time
12:19UA 4878 from Mobile at the gate
08:05DL 2709 to Atlanta leaves the gate
19 h 46 apart on the timetable, overnight
DL 2709 leaves 19 h 46 after UA 4878 arrives on the timetable: more than half a day, so not a connection we count.