DL 2751 then DL 446 at JFK
Detroit → New York → San Juan
Timetable, New York time
11:57DL 2751 from Detroit at the gate
12:10DL 446 to San Juan leaves the gate
13 min apart on the timetable
The last days
DL 2751 and DL 446 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.