AA 2556 then UA 4550 at O'Hare
San Diego → Chicago → Columbia Regional
Timetable, Chicago time
19:59AA 2556 from San Diego at the gate
19:45UA 4550 to Columbia Regional leaves the gate
23 h 46 apart on the timetable, overnight
UA 4550 leaves 23 h 46 after AA 2556 arrives on the timetable: more than half a day, so not a connection we count.