Norwegian is by far the best transatlantic ultra-low-cost carrier. With the introduction of international basic economy by United, Delta, and American, I personally consider Norwegian a low-cost carrier rather than an ultra-low-cost carrier. The only difference now between the traditional airlines and Norwegian is the payment for food and drinks.
They mainly operate brand new the 787 Dreamliner and the 737-Max and are planning a major expansion into the United States.
Airline Website: Nowegian.com
Long Haul Fees: Carry on bag (free if under 22 pounds), checked bag ($45), Seat Selection ($45), non-alcoholic drinks ($4-5), alcoholic drinks ($7-15), snacks ($4-8), fresh food ($10), and pre-ordered meals ($45).
Comparing prices to traditional carriers I would add: Carry on only: $50 round-trip or Checked bag only: $140 round-trip
US Departures: Austin, Boston, Chicago, Denver, Las Vegas, Los Angeles (LAX), Miami, New York City (JFK, EWR, SWF), Orlando, Providence, San Francisco, Seattle, and Tampa.
Hubs: London, Oslo, Copenhagen, and Stockholm
Fleet: Current Aircraft Fleet, Aircraft Deliveries, and Average Age of Planes (Norwegian will have 42 Dreamliners by 2020 and has 100 787-Max planes on order)
Seat Maps by Plane: SeatGuru