The Boeing Next-Generation 737 airplane is now assembled in 11 days at the company's Renton, Wash., facility, making it the shortest final assembly time of any large commercial jet. The assembly time reduction is due to the application of lean manufacturing techniques, which were introduced in late 1999. The 737's moving assembly line is the most compelling symbol of the factory's lean improvements. That line moves products from one assembly team to the next at the steady pace of two inches per minute.