Boeing sets 300 plane order, plant with China: report

US aerospace giant Boeing has reached deals with Chinese firms to sell 300 aircraft and open a completion centre in the Asian country, China's official Xinhua news agency reported, as President Xi Jinping began his first state visit to the United States.

The order, which was not immediately confirmed by Boeing, demonstrates the vital importance of the massive Chinese market despite a growth slowdown in the world's second largest economy that threatens to cut into the expansion of air travel.

The state-owned Commercial Aircraft Corporation of China (COMAC) also signed an agreement with Boeing yesterday to set up a "completion centre" in China for its narrow-body 737 airliners, Xinhua said, as the US company lifts competition with European rival Airbus, which already has a manufacturing presence.

The Xinhua report, datelined from Seattle where Xi started his trip yesterday, gave no immediate details of the models of the planes bought by a group of Chinese companies or the value of the sale.

But it is likely to be one of the biggest orders of recent times.

Xi is due to visit Boeing's main aeroplane factory in Washington state today, as he looks to highlight the economic importance of China to US firms with the countries' political relationship beset by tensions.

"China's rapidly growing aviation market plays a crucial role in our current and future success," Boeing chairman Jim McNerney said in a statement issued last week to announce the visit.

Later in his trip Xi will travel to Washington DC to meet US President Barack Obama at the White House.

China is expected to add 6,330 new aircraft worth $950 billion to its commercial fleet by 2034, Boeing said last month in its annual China Current Market Outlook.

The forecast comes despite current economic pain in China where growth slowed to 7.0 per cent for both the first and second quarters, weaker than 7.3 per cent for all of 2014 -- the worst in 24 years.