Delta and SkyTeam partners have round-trip flights from New York (JFK) to Brussels or Zurich (BRU/ZRH) for $319, NONSTOP. Flights November to March. Holiday Blackouts apply. Expect prices to fluctuate by about +/- $10. Flight may operate as a KLM/Air France codeshare. 8-day minimum stay required.
Note: Fare allows for a free carry-on bag, but checked bag will cost about +$60 each-way. Upgrades into “Regular Economy” are available for about +$90 each-way.