UA 1241 then DL 2709 at Houston
Denver → Houston → Atlanta
Timetable, Houston time
13:34UA 1241 from Denver at the gate
08:05DL 2709 to Atlanta leaves the gate
18 h 31 apart on the timetable, overnight
DL 2709 leaves 18 h 31 after UA 1241 arrives on the timetable: more than half a day, so not a connection we count.