LA 6139 then QF 4397 at San Francisco
Boston → San Francisco → Philadelphia
Timetable, San Francisco time
23:58LA 6139 from Boston at the gate
22:58QF 4397 to Philadelphia leaves the gate
23 h apart on the timetable, overnight
QF 4397 leaves 23 h after LA 6139 arrives on the timetable: more than half a day, so not a connection we count.