DL 5603 then B6 817 at Boston
Madison → Boston → New York JFK
Timetable, Boston time
18:52DL 5603 from Madison at the gate
18:39B6 817 to New York JFK leaves the gate
23 h 47 apart on the timetable, overnight
B6 817 leaves 23 h 47 after DL 5603 arrives on the timetable: more than half a day, so not a connection we count.