AA 215 then UA 3910 at O'Hare
Cancún → Chicago → Newark
Timetable, Chicago time
17:40AA 215 from Cancún at the gate
07:30UA 3910 to Newark leaves the gate
13 h 50 apart on the timetable, overnight
UA 3910 leaves 13 h 50 after AA 215 arrives on the timetable: more than half a day, so not a connection we count.