Boeing says the 737 MAX 8 uses around 20 per cent less fuel and produces fewer emissions than the aircraft it replaces. Vietnam Airlines said the investment will help improve operational efficiency and control costs, adding to a fleet that already includes Boeing 787 Dreamliners on regional and international routes, including services to Europe. The 737 MAX will mark the airline's first Boeing-built narrow-body aircraft, creating a combined fleet of single-aisle jets for shorter routes and Dreamliners for long-haul flying.