AA 2389 then AA 9827 at O'Hare
Calgary → Chicago → South Bend
Timetable, Chicago time
18:44AA 2389 from Calgary at the gate
19:21AA 9827 to South Bend leaves the gate
37 min apart on the timetable
The last days
AA 2389 and AA 9827 weren’t both flown 15 min to 12 h apart in the last 21 days.
Statistics from past flights, not live flight information. Always check times and your connection with your airline, and don’t base travel or booking decisions on these numbers.