UA 3994 then DL 2709 at Houston
El Paso → Houston → Atlanta
Timetable, Houston time
11:04UA 3994 from El Paso at the gate
08:05DL 2709 to Atlanta leaves the gate
21 h 01 apart on the timetable, overnight
DL 2709 leaves 21 h 01 after UA 3994 arrives on the timetable: more than half a day, so not a connection we count.