UA 5282 then AA 3484 at O'Hare
Colorado Springs → Chicago → St Louis
Timetable, Chicago time
11:56UA 5282 from Colorado Springs at the gate
09:30AA 3484 to St Louis leaves the gate
21 h 34 apart on the timetable, overnight
AA 3484 leaves 21 h 34 after UA 5282 arrives on the timetable: more than half a day, so not a connection we count.