AA 3762 then UA 4550 at O'Hare
Baltimore → Chicago → Columbia Regional
Timetable, Chicago time
19:59AA 3762 from Baltimore 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 3762 arrives on the timetable: more than half a day, so not a connection we count.