The jet will seat five passengers abreast in a cabin that is just 6 inches narrower than the six-abreast 737. A mock-up of the interior on display in Farnborough featured wide coach-class seats. It comes in 110- and 130-seater versions, the size of a Boeing 737-600 or 737-700 respectively.

The CSeries will be available starting in 2013 and will have a list price of about $47 million, executives said. The list price of a 737-700 is about $62 million.

Scott said the plane will burn as little as 0.85 gallon of fuel per passenger per 100 miles, "a new benchmark as little as two liters of fuel per passenger per 100 kilometer."

About 12 percent of that projected advantage comes from the new Pratt & Whitney geared turbofan engine. The rest comes from aerodynamic improvements.

The new engine also produces one fifth less carbon-dioxide emissions and will be four times quieter than other jets, making the CSeries "the greenest single-aisle aircraft in its class," said Scott.

The CSeries fuselage will be built in Shenyang, China, from a light aluminum/lithium alloy and shipped complete to the final-assembly site in Montreal.

The wings, made from carbon-fiber-reinforced composites, will be built in Belfast, Northern Ireland.

Bombardier said one-third of the plane's development costs of about $3.2 billion will be financed by the company and one-third by its suppliers.

The remaining third will come from governments of Canada and Britain and the regional governments of Quebec and Northern Ireland.

CSeries program director Benjamin Boehm said the plane will be 20 percent more efficient than the smaller regional jets of Embraer, with an even higher percentage advantage — "in the high 20s" — over the Boeing jets.