AA 4504 then UA 2769 at O'Hare
South Bend → Chicago → Denver
Timetable, Chicago time
18:35AA 4504 from South Bend at the gate
15:56UA 2769 to Denver leaves the gate
21 h 21 apart on the timetable, overnight
UA 2769 leaves 21 h 21 after AA 4504 arrives on the timetable: more than half a day, so not a connection we count.