AA 5510 then DL 866 at Atlanta
Washington National → Atlanta → Lexington
Timetable, Atlanta time
23:23AA 5510 from Washington National at the gate
20:15DL 866 to Lexington leaves the gate
20 h 52 apart on the timetable, overnight
DL 866 leaves 20 h 52 after AA 5510 arrives on the timetable: more than half a day, so not a connection we count.