F9 1596 then DL 1102 at Atlanta
Chicago O'Hare → Atlanta → St Louis
Timetable, Atlanta time
13:32F9 1596 from Chicago O'Hare at the gate
12:40DL 1102 to St Louis leaves the gate
23 h 08 apart on the timetable, overnight
DL 1102 leaves 23 h 08 after F9 1596 arrives on the timetable: more than half a day, so not a connection we count.