Boeing is closing ​in on one ‌of the largest sales ​in its ​history, a 500-aircraft order ⁠for ​737 Max jets ​set to be unveiled when U.S. ​President ​Donald Trump travels to ‌Beijing ⁠for his first state visit to ​China ​since ⁠2017, Bloomberg News ​reported on ​Friday, ⁠citing people familiar with ⁠the ​matter.