AA 2645 then UA 4772 at O'Hare
Houston → Chicago → Columbia Regional
Timetable, Chicago time
17:29AA 2645 from Houston at the gate
12:45UA 4772 to Columbia Regional leaves the gate
19 h 16 apart on the timetable, overnight
UA 4772 leaves 19 h 16 after AA 2645 arrives on the timetable: more than half a day, so not a connection we count.