UA 3902 then AA 4780 at O'Hare
Rio De Janeiro → Chicago → Buffalo
Timetable, Chicago time
17:01UA 3902 from Rio De Janeiro at the gate
08:00AA 4780 to Buffalo leaves the gate
14 h 59 apart on the timetable, overnight
AA 4780 leaves 14 h 59 after UA 3902 arrives on the timetable: more than half a day, so not a connection we count.