AA 642 then UA 5720 at O'Hare
Dallas-Fort Worth → Chicago → Washington National
Timetable, Chicago time
13:10AA 642 from Dallas-Fort Worth at the gate
10:14UA 5720 to Washington National leaves the gate
21 h 04 apart on the timetable, overnight
UA 5720 leaves 21 h 04 after AA 642 arrives on the timetable: more than half a day, so not a connection we count.