AA 4504 then UA 3484 at O'Hare
South Bend → Chicago → Pittsburgh
Timetable, Chicago time
18:35AA 4504 from South Bend at the gate
15:45UA 3484 to Pittsburgh leaves the gate
21 h 10 apart on the timetable, overnight
UA 3484 leaves 21 h 10 after AA 4504 arrives on the timetable: more than half a day, so not a connection we count.