UA 3993 then DL 2709 at Houston
Greenville-Spartanburg → Houston → Atlanta
Timetable, Houston time
08:45UA 3993 from Greenville-Spartanburg at the gate
08:05DL 2709 to Atlanta leaves the gate
23 h 20 apart on the timetable, overnight
DL 2709 leaves 23 h 20 after UA 3993 arrives on the timetable: more than half a day, so not a connection we count.