AA 1356 then DL 5804 at JFK
Las Vegas → New York → Boston
Timetable, New York time
07:11AA 1356 from Las Vegas at the gate
13:20DL 5804 to Boston leaves the gate
6 h 09 apart on the timetable
The last days
AA 1356 and DL 5804 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.