AA 6486 then UA 4644 at O'Hare
Detroit → Chicago → Detroit
Timetable, Chicago time
17:29AA 6486 from Detroit at the gate
15:00UA 4644 to Detroit leaves the gate
21 h 31 apart on the timetable, overnight
UA 4644 leaves 21 h 31 after AA 6486 arrives on the timetable: more than half a day, so not a connection we count.