AA 4504 then UA 5853 at O'Hare
South Bend → Chicago → Saginaw
Timetable, Chicago time
18:35AA 4504 from South Bend at the gate
10:37UA 5853 to Saginaw leaves the gate
16 h 02 apart on the timetable, overnight
UA 5853 leaves 16 h 02 after AA 4504 arrives on the timetable: more than half a day, so not a connection we count.