F9 3990 then DL 5478 at Detroit
Dallas-Fort Worth → Detroit → Cincinnati
Timetable, Detroit time
21:43F9 3990 from Dallas-Fort Worth at the gate
21:30DL 5478 to Cincinnati leaves the gate
23 h 47 apart on the timetable, overnight
DL 5478 leaves 23 h 47 after F9 3990 arrives on the timetable: more than half a day, so not a connection we count.