AA 802 then B6 8367 at Boston
Chicago O'Hare → Boston → New York JFK
Timetable, Boston time
12:07AA 802 from Chicago O'Hare at the gate
16:00B6 8367 to New York JFK leaves the gate
3 h 53 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 802 and B6 8367 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.