AA 4504 then UA 1946 at O'Hare
South Bend → Chicago → Pittsburgh
Timetable, Chicago time
18:35AA 4504 from South Bend at the gate
18:10UA 1946 to Pittsburgh leaves the gate
23 h 35 apart on the timetable, overnight
UA 1946 leaves 23 h 35 after AA 4504 arrives on the timetable: more than half a day, so not a connection we count.