B6 2901 then B6 615 at JFK
Buffalo → New York → San Francisco
Timetable, New York time
18:43B6 2901 from Buffalo at the gate
17:55B6 615 to San Francisco leaves the gate
23 h 12 apart on the timetable, overnight
B6 615 leaves 23 h 12 after B6 2901 arrives on the timetable: more than half a day, so not a connection we count.