Boeing [NYSE: BA] today begins final assembly of the 5,000th 737 in the Boeing manufacturing facility in Renton, Wash. The airplane, a 737-700 destined for Southwest Airlines, will be delivered next month. The wings and landing gear shown here are being joined to the 737-700 fuselage. Last-stage assembly and interiors installation will begin once the airplane joins the moving assembly line. In December 2005, sales for the 737 surpassed 6,000. To date, 231 customers have ordered 6,099 of the single-aisle passenger jet, which Boeing has manufactured since 1967.