DL 5223 then DL 5595 at JFK
Buffalo → New York → Washington
Timetable, New York time
12:48DL 5223 from Buffalo at the gate
10:25DL 5595 to Washington leaves the gate
21 h 37 apart on the timetable, overnight
DL 5595 leaves 21 h 37 after DL 5223 arrives on the timetable: more than half a day, so not a connection we count.