DL 813 then DL 1697 at Phoenix
Detroit → Phoenix → Boston
Timetable, Phoenix time
15:06DL 813 from Detroit at the gate
23:20DL 1697 to Boston leaves the gate
8 h 14 apart on the timetable
The last days
DL 813 and DL 1697 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.