DL 1187 then DL 9907 at Boston
Detroit → Boston → New York JFK
Timetable, Boston time
23:54DL 1187 from Detroit at the gate
10:00DL 9907 to New York JFK leaves the gate
10 h 06 apart on the timetable, overnight
The last days
DL 1187 and DL 9907 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.