UA 2135 then DL 2709 at Houston
Seattle → Houston → Atlanta
Timetable, Houston time
13:21UA 2135 from Seattle at the gate
08:05DL 2709 to Atlanta leaves the gate
18 h 44 apart on the timetable, overnight
DL 2709 leaves 18 h 44 after UA 2135 arrives on the timetable: more than half a day, so not a connection we count.