AA 642 then UA 5593 at O'Hare
Dallas-Fort Worth → Chicago → Memphis
Timetable, Chicago time
13:10AA 642 from Dallas-Fort Worth at the gate
08:43UA 5593 to Memphis leaves the gate
19 h 33 apart on the timetable, overnight
UA 5593 leaves 19 h 33 after AA 642 arrives on the timetable: more than half a day, so not a connection we count.