AA 4987 then UA 3376 at O'Hare
Flint → Chicago → St Louis
Timetable, Chicago time
18:15AA 4987 from Flint at the gate
11:00UA 3376 to St Louis leaves the gate
16 h 45 apart on the timetable, overnight
UA 3376 leaves 16 h 45 after AA 4987 arrives on the timetable: more than half a day, so not a connection we count.