UA 3902 then AA 1503 at O'Hare
Rio De Janeiro → Chicago → Cancún
Timetable, Chicago time
17:01UA 3902 from Rio De Janeiro at the gate
08:25AA 1503 to Cancún leaves the gate
15 h 24 apart on the timetable, overnight
AA 1503 leaves 15 h 24 after UA 3902 arrives on the timetable: more than half a day, so not a connection we count.