DL 452 then DL 2003 at JFK
Seattle → New York → Miami
Timetable, New York time
07:11DL 452 from Seattle at the gate
13:30DL 2003 to Miami leaves the gate
6 h 19 apart on the timetable
The last days
DL 452 and DL 2003 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.