AA 4521 then AA 479 at Boston
Rochester → Boston → Dallas-Fort Worth
Timetable, Boston time
06:30AA 4521 from Rochester at the gate
10:10AA 479 to Dallas-Fort Worth leaves the gate
3 h 40 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 4521 and AA 479 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.