UA 3941 then BA 7545 at San Francisco
Washington → San Francisco → Seattle
Timetable, San Francisco time
14:07UA 3941 from Washington at the gate
20:58BA 7545 to Seattle leaves the gate
6 h 51 apart on the timetable
The last days
UA 3941 and BA 7545 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.