AA 642 then AA 4780 at O'Hare
Dallas-Fort Worth → Chicago → Buffalo
Timetable, Chicago time
13:10AA 642 from Dallas-Fort Worth at the gate
08:00AA 4780 to Buffalo leaves the gate
18 h 50 apart on the timetable, overnight
AA 4780 leaves 18 h 50 after AA 642 arrives on the timetable: more than half a day, so not a connection we count.