AA 6501 then UA 4535 at O'Hare
Nashville → Chicago → Pittsburgh
Timetable, Chicago time
08:35AA 6501 from Nashville at the gate
12:48UA 4535 to Pittsburgh leaves the gate
4 h 13 apart on the timetable
The last days
AA 6501 and UA 4535 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.