DL 1697 then DL 977 at Boston
Phoenix → Boston → San Francisco
Timetable, Boston time
21:00DL 1697 from Phoenix at the gate
07:50DL 977 to San Francisco leaves the gate
10 h 50 apart on the timetable, overnight
The last days
DL 1697 and DL 977 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.