AA 1696 then UA 3376 at O'Hare
Atlanta → Chicago → St Louis
Timetable, Chicago time
16:31AA 1696 from Atlanta at the gate
11:00UA 3376 to St Louis leaves the gate
18 h 29 apart on the timetable, overnight
UA 3376 leaves 18 h 29 after AA 1696 arrives on the timetable: more than half a day, so not a connection we count.