Norwegian Airlines is putting direct flights from New York City to London, England on sale! Flights start at $332 round-trip, after taxes with very good availability from October 2017 through March 2018.
Note that flights originate from JFK to London Gatwick (LGW) and return from LGW to LaGuardia (LGA).
To find this deal, use Google Flights and search for business class flights between NYC and LON.