* China seen buying 8,090 new planes worth nearly $1.3 trln by 2038
* Previous estimate was for China to buy 7,690 planes by 2037 (Adds background, details)
BEIJING, Sept 17 (Reuters) - Boeing Co on Tuesday raised its forecast for China's aircraft demand for the next 20 years, underpinned by expectations of robust air travel demand, but growth in new fleet will be slower than the planemaker's prediction last year.
Chinese carriers will need 8,090 new planes through 2038, 5.2% higher than Boeing's forecast last year. That would be worth nearly $1.3 trillion based on list prices.
Last year, Boeing forecast a 6.2% growth in the country's new aircraft demand to 7,690 planes for the period to 2037.
"An expanding middle class, significant investment in infrastructure, and advanced technologies that make airplanes more capable and efficient, continue to drive tremendous demand for air travel," said Randy Tinseth, vice president of commercial marketing for Boeing.
Boeing and its European rival, Airbus, have been jostling to increase market share in China, the world's fastest growing aviation market, with both opening assembly plants in the country.
But the global grounding of Boeing's 737 MAX fleet in the wake of two fatal crashes have constrained the ability of Chinese airlines to expand capacity, with softer travel demand pressuring passenger yields amid a slowing economy.
Boeing projected a need for 5,960 new single-aisle airplanes over the next 20 years, representing 74% of total new deliveries, while China's widebody fleet will require 1,780 new planes, tripling the country's current widebody fleet size.
China will also need about $1.6 trillion worth of commercial services for its aircraft fleet over the period, Boeing said. (Reporting by Stella Qiu and Brenda Goh Editing by Shri Navaratnam and Saumyadeb Chakrabarty)