The 9999th Boeing 737-800 aircraft prepares to take off from the company's Seattle airfield in the state of Washington, the United States, March 24, 2018. China's air carrier Okay Airways witnessed Saturday the 9999th Boeing 737-800 aircraft delivered by the Boeing Company embarked on a home-bound journey back to China from the United States. (Xinhua/Wu Xiaoling)

SAN FRANCISCO, March 24 (Xinhua) -- China's air carrier Okay Airways witnessed Saturday the 9999th Boeing 737-800 aircraft delivered by the Boeing Company embarked on a home-bound journey back to China from the United States.

The 737-800 jet, which was officially delivered by Boeing on Friday, took off from the company's Seattle airfield in the state of Washington on the west coast, and will make a stopover at Hawaii and Saipan, the largest island of the Northern Mariana Islands in the western Pacific Ocean, before it arrives at Tianjin Binhai International Airport.

The new delivery will expand Okay Airways's Boeing fleet to 27.

Erik Nelson, vice president of Boeing 737 Field Operations and Delivery, said that the figure of 9999 means eternity in Chinese culture, and that Boeing and the Chinese air industry will continue to deepen their long-term relations of friendship and cooperation.

Rick Anderson, vice president of Northeast Asia Sales of Boeing Commercial Airplanes based in Seattle, said Boeing has maintained a great cooperation relationship with Okay Airways, the first private air carrier in China.

Wang Shusheng, president of Okay Airways, said that his company has kept a close cooperation with Boeing in many areas, citing a pilot training program the airline recently signed with Boeing in Shanghai in east China.

"The delivery of the 9999th aircraft is a manifestation of the deepened cooperation between the two sides," he said.

The future addition of Boeing 737 MAX series and 787-9 Dreamliners to the fleet of Okay Airways will generate more opportunities for the airline's development, Wang said.

The new 737-800 jet will be put into service by the end of March, with its first commercial fight expected to be scheduled from Tianjin in northern China to Changsha, capital of Hunan province in central China.

The 737 family is the fastest-selling airplane in Boeing history, accumulating more than 14,545 orders from 425 global customers of Boeing Commercial Airplanes by the end of February 2018.

Boeing celebrated the 10,000th 737 aircraft that rolled off its production line on March 13 this year.