AA 3977 then K4 578 at O'Hare
Detroit → Chicago → Seoul
Timetable, Chicago time
14:05AA 3977 from Detroit at the gate
07:40K4 578 to Seoul leaves the gate
17 h 35 apart on the timetable, overnight
K4 578 leaves 17 h 35 after AA 3977 arrives on the timetable: more than half a day, so not a connection we count.