AA 2748 then UA 4550 at O'Hare
Las Vegas → Chicago → Columbia Regional
Timetable, Chicago time
20:07AA 2748 from Las Vegas at the gate
19:45UA 4550 to Columbia Regional leaves the gate
23 h 38 apart on the timetable, overnight
UA 4550 leaves 23 h 38 after AA 2748 arrives on the timetable: more than half a day, so not a connection we count.