AA 4504 then UA 2226 at O'Hare
South Bend → Chicago → Buffalo
Timetable, Chicago time
18:35AA 4504 from South Bend at the gate
14:18UA 2226 to Buffalo leaves the gate
19 h 43 apart on the timetable, overnight
UA 2226 leaves 19 h 43 after AA 4504 arrives on the timetable: more than half a day, so not a connection we count.