AA 4517 then AA 866 at Boston
Rochester → Boston → Chicago O'Hare
Timetable, Boston time
12:58AA 4517 from Rochester at the gate
13:30AA 866 to Chicago O'Hare leaves the gate
32 min 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 4517 and AA 866 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.