The Dreamliner uses plastic composites instead of aluminum.
Up to 50 per cent of the primary structure, including the fuselage and wing, will be made of composites such as carbon-fibre, which reduce the weight of the aircraft.
Boeing said in a statement ahead of the Dreamliner's unveiling: "By manufacturing a one-piece fuselage section, we are eliminating 1,500 aluminum sheets and 40,000 to 50,000 fasteners.
"The airplane will use 20 per cent less fuel for comparable missions than today's similarly sized airplane."
With the promise of lower fuel costs at a time of rising oil prices in a sector where profit margins are already razor-thin, Boeing hopes to attract buyers.
The company, which aims to build 2,000 Dreamliners over the next 20 years, has so far received 642 orders from 46 companies for the aircraft, which has a catalogue price of between $146m and $200m.
The Dreamliner comes in three models for both medium- and long-haul flights with a seating capacity of between 210 to 330 places.
Able to fly up to 15,750km without refuelling, it can fly routes such as New York to Manila, or Moscow to Sao Paulo, journeys which are so far only open to bigger aircraft.
The 787 will go into service after Airbus's giant A380 takes to the skies.
The first units of the European double-decker superjumbo, capable of seating up to 800 passengers, will be delivered to Singapore Airlines in October.
Analysts say the Dreamliner and the A380 reflect the different strategies of Boeing and Airbus as they seek to achieve the same objective, namely cheaper air travel.