American Airlines offers nonstop flights for travel from New York JFK to Cancun CUN at $318 with fall dates from August into December. This fare has many available departure dates all the way to December, with the exception of Thanksgiving week travel.
American Airlines New York JFK – Cancun CUN
$317.20 Sunday, December 6 – Saturday December 12
There are even lower fares with out of Newark EWR down to $239 round trip for summer travel, but itineraries require a two-segment routing with overnight layover in Charlotte or some other hub.
American Airlines Newark EWR – Cancun CUN
$244.31 Friday, August 21 – Thursday, August 27