KE 91 then DL 5597 at Boston
Seoul → Boston → Jacksonville
Timetable, Boston time
08:50KE 91 from Seoul at the gate
08:45DL 5597 to Jacksonville leaves the gate
23 h 55 apart on the timetable, overnight
DL 5597 leaves 23 h 55 after KE 91 arrives on the timetable: more than half a day, so not a connection we count.