AS 120 then DL 438 at Seattle
Seoul → Seattle → Boston
Timetable, Seattle time
12:55AS 120 from Seoul at the gate
11:45DL 438 to Boston leaves the gate
22 h 50 apart on the timetable, overnight
DL 438 leaves 22 h 50 after AS 120 arrives on the timetable: more than half a day, so not a connection we count.