UA 6015 then AA 3484 at O'Hare
Milwaukee → Chicago → St Louis
Timetable, Chicago time
10:00UA 6015 from Milwaukee at the gate
09:30AA 3484 to St Louis leaves the gate
23 h 30 apart on the timetable, overnight
AA 3484 leaves 23 h 30 after UA 6015 arrives on the timetable: more than half a day, so not a connection we count.