AA 4783 then UA 3376 at O'Hare
Baltimore → Chicago → St Louis
Timetable, Chicago time
12:59AA 4783 from Baltimore at the gate
11:00UA 3376 to St Louis leaves the gate
22 h 01 apart on the timetable, overnight
UA 3376 leaves 22 h 01 after AA 4783 arrives on the timetable: more than half a day, so not a connection we count.