AA 1277 then UA 4772 at O'Hare
Denver → Chicago → Columbia Regional
Timetable, Chicago time
18:19AA 1277 from Denver at the gate
12:45UA 4772 to Columbia Regional leaves the gate
18 h 26 apart on the timetable, overnight
UA 4772 leaves 18 h 26 after AA 1277 arrives on the timetable: more than half a day, so not a connection we count.