AA 9914 then UA 5566 at O'Hare
Detroit → Chicago → Pittsburgh
Timetable, Chicago time
10:20AA 9914 from Detroit at the gate
14:16UA 5566 to Pittsburgh leaves the gate
3 h 56 apart on the timetable
The last days
AA 9914 and UA 5566 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.