AA 4504 then UA 422 at O'Hare
South Bend → Chicago → Portland (Maine)
Timetable, Chicago time
18:35AA 4504 from South Bend at the gate
10:50UA 422 to Portland (Maine) leaves the gate
16 h 15 apart on the timetable, overnight
UA 422 leaves 16 h 15 after AA 4504 arrives on the timetable: more than half a day, so not a connection we count.