DL 3990 then UA 4749 at Detroit
Louisville → Detroit → Chicago O'Hare
Timetable, Detroit time
12:04DL 3990 from Louisville at the gate
10:48UA 4749 to Chicago O'Hare leaves the gate
22 h 44 apart on the timetable, overnight
UA 4749 leaves 22 h 44 after DL 3990 arrives on the timetable: more than half a day, so not a connection we count.