DL 5600 then DL 5620 at Boston
Washington National → Boston → Cincinnati
Timetable, Boston time
17:11DL 5600 from Washington National at the gate
17:00DL 5620 to Cincinnati leaves the gate
23 h 49 apart on the timetable, overnight
DL 5620 leaves 23 h 49 after DL 5600 arrives on the timetable: more than half a day, so not a connection we count.