UA 5210 then AA 3484 at O'Hare
Saginaw → Chicago → St Louis
Timetable, Chicago time
10:10UA 5210 from Saginaw at the gate
09:30AA 3484 to St Louis leaves the gate
23 h 20 apart on the timetable, overnight
AA 3484 leaves 23 h 20 after UA 5210 arrives on the timetable: more than half a day, so not a connection we count.