AA 551 then AA 1232 at Philadelphia
Miami → Philadelphia → Boston
Timetable, Philadelphia time
11:56AA 551 from Miami at the gate
20:12AA 1232 to Boston leaves the gate
8 h 16 apart on the timetable
The last days
AA 551 and AA 1232 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.