AA 4521 then AA 547 at Boston
Rochester → Boston → Chicago O'Hare
Timetable, Boston time
06:30AA 4521 from Rochester at the gate
13:25AA 547 to Chicago O'Hare leaves the gate
6 h 55 apart on the timetable
The last days
AA 4521 and AA 547 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.