B6 316 then B6 818 at JFK
San Francisco → New York → Boston
Timetable, New York time
21:06B6 316 from San Francisco at the gate
17:48B6 818 to Boston leaves the gate
20 h 42 apart on the timetable, overnight
B6 818 leaves 20 h 42 after B6 316 arrives on the timetable: more than half a day, so not a connection we count.