UA 5337 then AA 3484 at O'Hare
Green Bay → Chicago → St Louis
Timetable, Chicago time
09:37UA 5337 from Green Bay at the gate
09:30AA 3484 to St Louis leaves the gate
23 h 53 apart on the timetable, overnight
AA 3484 leaves 23 h 53 after UA 5337 arrives on the timetable: more than half a day, so not a connection we count.