State-owned companies in Russia and China have been working together on a wide-body jet program since 2014 and was originally planned to enter the market by 2025.
Russia's United Aircraft Corporation (UAC) and the Commercial Aircraft Corporation of China (COMAC) are building the CR929, a long-range, 250-320-seat, wide-body plane powered by two engines. The joint venture, headquartered in Shanghai, operates under the name CRAIC.
CNBC reached out to UAC and COMAC but a comment was not immediately available.
Last year, Boeing forecasted that the Chinese civil aerospace market, considered the world' second largest after the United States, will grow over the next couple of decades by around 7690 planes, loosely estimated at around $1.2 trillion of business.
The CR929 is aimed at winning a slice of the growing aviation pie and is particularly focused on the long-range routes currently dominated by Boeing's 787 and the Airbus A350.
The firms jointly unveiled a full-size model of the plane at the November 2018 Zhuhai Airshow in China where COMAC maintained that a first customer delivery should happen by 2025. That date now looks in doubt after UAC said in June this year that while it had received its first preliminary orders, the first finished plane may now not appear until 2027.
CRAIC Program Director Xie Canjun told industry press in February this year that the concept design of the plane should be complete by early 2020.
"How wide and how long, the internal layout, the aircraft's basic functionality, what is the range, and passenger capacity, these have all been done," he said.
Russia will build the wings, but the plane's fuselage is to be built in China where final assembly will occur.
Aside from differing estimations on delivery dates, engine selection is offering further hints that communication between Russia and China is not operating smoothly.
General Electric and Rolls Royce are the two finalists to initially supply engines but a joint effort to develop a Sino-Russian engine for the Craic CR929 was announced at the Zhuhai show.
This news was immediately complicated by the Aero Engine Corp. of China (AECC) that displayed its own engine at the show. AECC executives claimed at the event that it hoped to be chosen as the supplier to ultimately power the plane.
Not to be outdone, Russia's United Engine Corporation (UEC) has also been included in the list of the CR929's potential suppliers. UEC is developing a turbofan engine which the manufacturer says would meet the needs of the CR929.