UA 3985 then DL 2709 at Houston
Des Moines → Houston → Atlanta
Timetable, Houston time
10:40UA 3985 from Des Moines at the gate
08:05DL 2709 to Atlanta leaves the gate
21 h 25 apart on the timetable, overnight
DL 2709 leaves 21 h 25 after UA 3985 arrives on the timetable: more than half a day, so not a connection we count.