AA 6434 then UA 3376 at O'Hare
Oklahoma City → Chicago → St Louis
Timetable, Chicago time
16:39AA 6434 from Oklahoma City at the gate
11:00UA 3376 to St Louis leaves the gate
18 h 21 apart on the timetable, overnight
UA 3376 leaves 18 h 21 after AA 6434 arrives on the timetable: more than half a day, so not a connection we count.