DL 8839 then B6 933 at Boston
Memphis → Boston → San Francisco
Timetable, Boston time
13:30DL 8839 from Memphis at the gate
17:05B6 933 to San Francisco leaves the gate
3 h 35 apart on the timetable
The last days
DL 8839 and B6 933 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.