UA 3902 then AA 2143 at O'Hare
Rio De Janeiro → Chicago → Boston
Timetable, Chicago time
17:01UA 3902 from Rio De Janeiro at the gate
08:29AA 2143 to Boston leaves the gate
15 h 28 apart on the timetable, overnight
AA 2143 leaves 15 h 28 after UA 3902 arrives on the timetable: more than half a day, so not a connection we count.