B6 64 then AA 3748 at Boston
Key West → Boston → Washington National
Timetable, Boston time
16:20B6 64 from Key West at the gate
07:30AA 3748 to Washington National leaves the gate
15 h 10 apart on the timetable, overnight
AA 3748 leaves 15 h 10 after B6 64 arrives on the timetable: more than half a day, so not a connection we count.