UA 3852 then DL 400 at San Francisco
Ontario → San Francisco → Boston
Timetable, San Francisco time
10:55UA 3852 from Ontario at the gate
07:00DL 400 to Boston leaves the gatealso VS 1787, SK 3586, LY 4228, AF 8859
20 h 05 apart on the timetable, overnight
DL 400 leaves 20 h 05 after UA 3852 arrives on the timetable: more than half a day, so not a connection we count.