AA 4400 then UA 4772 at O'Hare
Memphis → Chicago → Columbia Regional
Timetable, Chicago time
16:25AA 4400 from Memphis at the gate
12:45UA 4772 to Columbia Regional leaves the gate
20 h 20 apart on the timetable, overnight
UA 4772 leaves 20 h 20 after AA 4400 arrives on the timetable: more than half a day, so not a connection we count.