DL 5775 then DL 5840 at Boston
Washington National → Boston → New York LaGuardia
Timetable, Boston time
09:48DL 5775 from Washington National at the gate
22:00DL 5840 to New York LaGuardia leaves the gate
12 h 12 apart on the timetable
DL 5840 leaves 12 h 12 after DL 5775 arrives on the timetable: more than half a day, so not a connection we count.