AA 4504 then UA 2331 at O'Hare
South Bend → Chicago → Boston
Timetable, Chicago time
18:35AA 4504 from South Bend at the gate
18:00UA 2331 to Boston leaves the gate
23 h 25 apart on the timetable, overnight
UA 2331 leaves 23 h 25 after AA 4504 arrives on the timetable: more than half a day, so not a connection we count.