RENTON, Wash., Feb. 4, 2014 /PRNewswire/ — Boeing [NYSE: BA] is starting assembly this week of the first Next-Generation 737 to be built at the increased rate of 42 airplanes per month. Since 2010, production of the 737 has increased about 33 percent, from 31.5 to 42 airplanes a month, its highest rate ever.

Early Wednesday morning, mechanics will load initial parts of the spars – internal support structures in the wings – into an automated spar-assembly machine. The spar is the first step in building the wings and marks the start of the assembly of the airplane at the Renton, Wash. factory.

“This rate increase once again reflects our commitment to put the world’s best-selling airplane into the hands of our customers as quickly as possible,” said Beverly Wyse, vice president and general manager, 737 Program, Boeing Commercial Airplanes. “Efficiency improvements in the factory, many of them developed by our employees, are a big part of why we are able to successfully increase the number of airplanes we build.”

The first Next-Generation 737 built at the new rate is scheduled to be delivered in the second quarter. As previously announced, the 737 production rate is scheduled to increase to 47 airplanes a month in 2017.