DL 1581 then DL 1986 at Houston
Detroit → Houston → New York LaGuardia
Timetable, Houston time
10:27DL 1581 from Detroit at the gate
14:15DL 1986 to New York LaGuardia leaves the gate
3 h 48 apart on the timetable
The last days
DL 1581 and DL 1986 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.