China's Okay Airways takes delivery of 9999th Boeing 737-800 aircraft

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)