AA 5316 then UA 3376 at O'Hare
Louisville → Chicago → St Louis
Timetable, Chicago time
13:57AA 5316 from Louisville at the gate
11:00UA 3376 to St Louis leaves the gate
21 h 03 apart on the timetable, overnight
UA 3376 leaves 21 h 03 after AA 5316 arrives on the timetable: more than half a day, so not a connection we count.