"We are still a young company. The start-up investment has not been finalized yet," Jack Shi, senior vice president for commercial development of Eastern Air Lines, told Reuters.
He said the airline was shopping for planes to start services late next year from Miami to unspecified destinations in Latin America.
Shi said that, once reborn, Eastern wanted to be the first operator to fly COMAC jets in the United States just as it had introduced the European Airbus there.
Tian Min, COMAC's chief accountant, said that the market for narrow-bodied jumbo jets would be "huge" in the next 20 years.
The C919 is due to make its first flight in 2014 and enter service within two years after that, according to COMAC.
The Eastern Air Lines deal came on the heels of 50 C919 orders - 20 aircraft each from Joy Air and Hebei Aviation Group and 10 from General Electric Capital Aviation Services.
US-based GE Capital Aviation Services, the only foreign customer signing deals for the plane, also ordered 10 aircraft at the 2010 air show.
It isn't just ordering the C919s to support the program, Liu Li, its China general manager, told Bloomberg News.
"The world aviation market is so big and there's only two major makers," Liu said. "There is also a rising middle class, which will spur air travel."
Other potential C919 customers that have signed tentative agreements include Irish low-cost carrier Ryanair and British Airways, said COMAC.
The company is already building ARJ regional jets at the plant near Pudong International Airport and four planes are currently on test. It plans to make 50 such jets a year by 2014.
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