AA 434 then AA 857 at Boston
Miami (MIA) → Boston → Philadelphia
Timetable, Boston time
10:20AA 434 from Miami (MIA) at the gate
16:59AA 857 to Philadelphia leaves the gate
6 h 39 apart on the timetable
Boston’s board gives an arrival time for only about 58% of its flights, so many days show no gate time.
The last days
AA 434 and AA 857 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.