AA 4222 then UA 3376 at O'Hare
Green Bay → Chicago → St Louis
Timetable, Chicago time
16:00AA 4222 from Green Bay at the gate
11:00UA 3376 to St Louis leaves the gate
19 h apart on the timetable, overnight
UA 3376 leaves 19 h after AA 4222 arrives on the timetable: more than half a day, so not a connection we count.