AA 4504 then UA 1398 at O'Hare
South Bend → Chicago → Atlanta
Timetable, Chicago time
18:35AA 4504 from South Bend at the gate
18:15UA 1398 to Atlanta leaves the gate
23 h 40 apart on the timetable, overnight
UA 1398 leaves 23 h 40 after AA 4504 arrives on the timetable: more than half a day, so not a connection we count.