AA 1764 then UA 3376 at O'Hare
Austin → Chicago → St Louis
Timetable, Chicago time
18:45AA 1764 from Austin at the gate
11:00UA 3376 to St Louis leaves the gate
16 h 15 apart on the timetable, overnight
UA 3376 leaves 16 h 15 after AA 1764 arrives on the timetable: more than half a day, so not a connection we count.