American, Delta and Emirates Airlines all have New York JFK to Milan, Italy MXP at $499-$500 round trip for nonstop flights from October into May 2017.
Star Alliance member TAP Portugal has this route on sale for about $550 via Lisbon January to March, along with several other cities in Italy and around Europe.
American Airlines New York JFK – Milan MXP
Alitalia Airlines New York JFK – Milan MXP
Emirates Airlines New York JFK – Milan MXP