AA 376 then AA 591 at Charlotte
Pittsburgh → Charlotte → Denver
Timetable, Charlotte time
06:35AA 376 from Pittsburgh at the gate
13:28AA 591 to Denver leaves the gate
6 h 53 apart on the timetable
The last days
AA 376 and AA 591 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.