AA 4504 then DL 2570 at O'Hare
South Bend → Chicago → Boston
Timetable, Chicago time
18:35AA 4504 from South Bend at the gate
11:00DL 2570 to Boston leaves the gate
16 h 25 apart on the timetable, overnight
DL 2570 leaves 16 h 25 after AA 4504 arrives on the timetable: more than half a day, so not a connection we count.