KE 91 then DL 5851 at Boston
Seoul → Boston → Baltimore
Timetable, Boston time
08:50KE 91 from Seoul at the gate
21:15DL 5851 to Baltimore leaves the gate
12 h 25 apart on the timetable
DL 5851 leaves 12 h 25 after KE 91 arrives on the timetable: more than half a day, so not a connection we count.