AA 363 then UA 5539 at O'Hare
St Louis → Chicago → Moline
Timetable, Chicago time
06:29AA 363 from St Louis at the gate
21:47UA 5539 to Moline leaves the gate
15 h 18 apart on the timetable
UA 5539 leaves 15 h 18 after AA 363 arrives on the timetable: more than half a day, so not a connection we count.