B6 633 then KL 7451 at San Francisco
Boston → San Francisco → New York JFK
Timetable, San Francisco time
09:40B6 633 from Boston at the gate
20:50KL 7451 to New York JFK leaves the gate
11 h 10 apart on the timetable
The last days
B6 633 and KL 7451 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.