DL 8839 then DL 776 at Boston
Memphis → Boston → Miami
Timetable, Boston time
13:30DL 8839 from Memphis at the gate
15:55DL 776 to Miami leaves the gate
2 h 25 apart on the timetable
The last days
DL 8839 and DL 776 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.