AA 4151 then AA 4509 at O'Hare
Jacksonville → Chicago → Pittsburgh
Timetable, Chicago time
14:29AA 4151 from Jacksonville at the gate
18:24AA 4509 to Pittsburgh leaves the gate
3 h 55 apart on the timetable
The last days
AA 4151 and AA 4509 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.