AA 642 then UA 1856 at O'Hare
Dallas-Fort Worth → Chicago → Newark
Timetable, Chicago time
13:10AA 642 from Dallas-Fort Worth at the gate
10:39UA 1856 to Newark leaves the gate
21 h 29 apart on the timetable, overnight
UA 1856 leaves 21 h 29 after AA 642 arrives on the timetable: more than half a day, so not a connection we count.