AA 2504 then UA 4772 at O'Hare
Houston → Chicago → Columbia Regional
Timetable, Chicago time
14:15AA 2504 from Houston at the gate
12:45UA 4772 to Columbia Regional leaves the gate
22 h 30 apart on the timetable, overnight
UA 4772 leaves 22 h 30 after AA 2504 arrives on the timetable: more than half a day, so not a connection we count.