AA 516 then AA 547 at Boston
Washington National → Boston → Chicago O'Hare
Timetable, Boston time
09:38AA 516 from Washington National at the gate
13:25AA 547 to Chicago O'Hare leaves the gate
3 h 47 apart on the timetable
Boston’s board gives an arrival time for only about 59% of its flights, so many days show no gate time.
The last days
AA 516 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.