UA 3501 then AA 2208 at O'Hare
Kansas City → Chicago → St Louis
Timetable, Chicago time
17:05UA 3501 from Kansas City at the gate
09:30AA 2208 to St Louis leaves the gate
16 h 25 apart on the timetable, overnight
AA 2208 leaves 16 h 25 after UA 3501 arrives on the timetable: more than half a day, so not a connection we count.