AA 4724 then AA 3748 at Boston
New York LaGuardia → Boston → Washington National
Timetable, Boston time
18:56AA 4724 from New York LaGuardia at the gate
07:30AA 3748 to Washington National leaves the gate
12 h 34 apart on the timetable, overnight
AA 3748 leaves 12 h 34 after AA 4724 arrives on the timetable: more than half a day, so not a connection we count.