Star Alliance airlines offer low fares from New York JFK at $440 to Amsterdam or $443 to Brussels. These tickets are available with Austrian Airlines, Brussels Airlines, Swiss Airlines and Lufthansa for under $500 round trip for travel from January 11 to March 31. Lowest fares to Amsterdam are Brussels Airlines, but not a great itinerary. The other airlines offer one-stop itineraries via their country hub airports for a little more. Brussels Airlines flies JFK-BRU nonstop.
Swiss Airlines New York JFK – Zurich ZRH – Amsterdam AMS – ZRH – JFK
Brussels Airlines New York JFK – Brussels, Belgium BRU nonstop