B6 618 then AA 3748 at Boston
New York JFK → Boston → Washington National
Timetable, Boston time
16:59B6 618 from New York JFK at the gate
07:30AA 3748 to Washington National leaves the gate
14 h 31 apart on the timetable, overnight
AA 3748 leaves 14 h 31 after B6 618 arrives on the timetable: more than half a day, so not a connection we count.