It would take two to three years for the aircraft to reach the market, sources at COMAC told Chinese media on Friday.

But Qi Qi, an associate professor at Guangzhou Civil Aviation College, said it could take up to five years before mass production, and then at least another five years before the aircraft has caught up with Airbus and Boeing.

“I am not optimistic about the C919. I remain neutral," said Mr Qi, ahead of the test flight, which was delayed for a year following manufacturing problems.

“The test flight is just the first step of a Long March for the industry,” he added, referring to an arduous retreat by Mao Tse-tung’s Communists in the 1930s, which is sometimes mentioned in modern China in relation to long-term, difficult projects.

“We can’t say that everything is going perfectly even if the test goes well,” he added. “It still has a long way to go.”