AA 3546 then AA 1317 at O'Hare
Detroit → Chicago → Denver
Timetable, Chicago time
11:00AA 3546 from Detroit at the gate
15:20AA 1317 to Denver leaves the gate
4 h 20 apart on the timetable
The last days
AA 3546 and AA 1317 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.