UA 1388 then DL 2709 at Houston
Boston → Houston → Atlanta
Timetable, Houston time
13:12UA 1388 from Boston at the gate
08:05DL 2709 to Atlanta leaves the gate
18 h 53 apart on the timetable, overnight
DL 2709 leaves 18 h 53 after UA 1388 arrives on the timetable: more than half a day, so not a connection we count.