AA 5510 then DL 1403 at Atlanta
Washington National → Atlanta → St Louis
Timetable, Atlanta time
23:23AA 5510 from Washington National at the gate
23:10DL 1403 to St Louis leaves the gate
23 h 47 apart on the timetable, overnight
DL 1403 leaves 23 h 47 after AA 5510 arrives on the timetable: more than half a day, so not a connection we count.