AA 320 then AA 3073 at Philadelphia
Chicago O'Hare → Philadelphia → Boston
Timetable, Philadelphia time
11:41AA 320 from Chicago O'Hare at the gate
15:45AA 3073 to Boston leaves the gate
4 h 04 apart on the timetable
The last days
AA 320 and AA 3073 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.