UA 3943 then DL 2709 at Houston
Washington → Houston → Atlanta
Timetable, Houston time
13:47UA 3943 from Washington at the gate
08:05DL 2709 to Atlanta leaves the gate
18 h 18 apart on the timetable, overnight
DL 2709 leaves 18 h 18 after UA 3943 arrives on the timetable: more than half a day, so not a connection we count.