AA 3811 then UA 4772 at O'Hare
Omaha → Chicago → Columbia Regional
Timetable, Chicago time
17:57AA 3811 from Omaha at the gate
12:45UA 4772 to Columbia Regional leaves the gate
18 h 48 apart on the timetable, overnight
UA 4772 leaves 18 h 48 after AA 3811 arrives on the timetable: more than half a day, so not a connection we count.