AA 5405 then UA 3376 at O'Hare
Louisville → Chicago → St Louis
Timetable, Chicago time
19:30AA 5405 from Louisville at the gate
11:00UA 3376 to St Louis leaves the gate
15 h 30 apart on the timetable, overnight
UA 3376 leaves 15 h 30 after AA 5405 arrives on the timetable: more than half a day, so not a connection we count.