UA 3873 then DL 1389 at Houston
Kansas City → Houston → Detroit
Timetable, Houston time
10:47UA 3873 from Kansas City at the gate
05:10DL 1389 to Detroit leaves the gate
18 h 23 apart on the timetable, overnight
DL 1389 leaves 18 h 23 after UA 3873 arrives on the timetable: more than half a day, so not a connection we count.