UA 6104 then AA 1503 at O'Hare
South Bend → Chicago → Cancún
Timetable, Chicago time
19:00UA 6104 from South Bend at the gate
08:25AA 1503 to Cancún leaves the gate
13 h 25 apart on the timetable, overnight
AA 1503 leaves 13 h 25 after UA 6104 arrives on the timetable: more than half a day, so not a connection we count.