B6 1852 then DL 5123 at JFK
Cancún → New York → Jacksonville
Timetable, New York time
18:30B6 1852 from Cancún at the gate
18:20DL 5123 to Jacksonville leaves the gate
23 h 50 apart on the timetable, overnight
DL 5123 leaves 23 h 50 after B6 1852 arrives on the timetable: more than half a day, so not a connection we count.