AA 642 then UA 1620 at O'Hare
Dallas-Fort Worth → Chicago → Miami
Timetable, Chicago time
13:10AA 642 from Dallas-Fort Worth at the gate
10:43UA 1620 to Miami leaves the gate
21 h 33 apart on the timetable, overnight
UA 1620 leaves 21 h 33 after AA 642 arrives on the timetable: more than half a day, so not a connection we count.