AA 642 then UA 1491 at O'Hare
Dallas-Fort Worth → Chicago → Charleston (South Carolina)
Timetable, Chicago time
13:10AA 642 from Dallas-Fort Worth at the gate
10:40UA 1491 to Charleston (South Carolina) leaves the gate
21 h 30 apart on the timetable, overnight
UA 1491 leaves 21 h 30 after AA 642 arrives on the timetable: more than half a day, so not a connection we count.