Even before China’s domestically made C919 single-aisle jet takes flight, the nation already has its sights set on producing a much larger aircraft within a decade. Executives of state-owned Commercial Aircraft Corp. of China Ltd. unveiled plans Wednesday to make a twin-aisle jet that can fly as far as 12,000 kilometers—roughly the distance between Beijing and New York. The company, known as Comac, is forming a joint venture with Russia’s United Aircraft Corp. to research on and manufacture the aircraft. The announcement at a biennial airshow in southern Zhuhai city marks the first time China has given details of the widebody aircraft since the planned Russian partnership was flagged two years ago and comes amid delays to the maiden flight of the C919. The new plane would be able to seat 280 people, posing a direct challenge to jetliners from Boeing Co. and Airbus Group SE such as their current B777, B787, A330 and A350 models. Comac is targeting the maiden flight of the new aircraft to take place about seven years from now, and the first delivery three years after that. An assembly line will be set up in Shanghai, with an eye to exporting the plane to other markets in the future, said Guo Bozhi, an assistant president at Comac who’s in charge of the widebody-jet project. “Developing an aircraft is an arduous journey and we have to overcome a lot of technical difficulties,” Guo said at a briefing. But the timeframe “is a definite target,” he said. He declined to provide financial figures on the joint venture and development of the twin-engine plane. Comac said Tuesday that China Eastern Airlines Corp. will be the first carrier to take delivery of the locally made C919, a day after Wu Guanghui, Comac’s chief designer, said the narrowbody jet’s test flight would take place later this year or in early 2017. The plane’s maiden flight has been pushed back at least twice since 2014.