AA 3865 then AA 1778 at Charlotte
Hilton Head → Charlotte → Cancún
Timetable, Charlotte time
13:44AA 3865 from Hilton Head at the gate
13:10AA 1778 to Cancún leaves the gate
23 h 26 apart on the timetable, overnight
AA 1778 leaves 23 h 26 after AA 3865 arrives on the timetable: more than half a day, so not a connection we count.