UA 574 then VA 8287 at San Francisco
Boston → San Francisco → Seattle
Timetable, San Francisco time
12:49UA 574 from Boston at the gate
07:25VA 8287 to Seattle leaves the gate
18 h 36 apart on the timetable, overnight
VA 8287 leaves 18 h 36 after UA 574 arrives on the timetable: more than half a day, so not a connection we count.