In 2026, the cheapest European entry points from New York (JFK or Newark) are consistently London (LHR/LGW), Madrid (MAD), Lisbon (LIS), and Barcelona (BCN). These cities serve as massive transatlantic hubs with high flight frequencies, which keeps competition high and prices low. Budget carriers like Norse Atlantic often offer ultra-low fares into London Gatwick or Oslo, while legacy carriers like Iberia and TAP Air Portugal provide very competitive rates into Madrid and Lisbon respectively. On average, a round-trip flight to these destinations can range from $350 to $600 in the off-peak season. If you are looking for the absolute lowest cost, flying into London or Lisbon and then using a local low-cost carrier like Ryanair or easyJet to reach your final destination in Europe is a proven strategy to save hundreds of dollars compared to booking a direct flight to a secondary city like Prague or Rome.