Posted by John McHale SEATTLE, 3 July 2010.Boeing (NYSE: BA) finalized an order with Air China, the flag carrier of the People's Republic of China, for 20 Next-Generation 737-800 jetliners. Air China operates international and domestic passenger and cargo services. The carrier will use the airplanes to expand its domestic routes. Boeing announced in June that it will increase production rates on the Next-Generation 737 program to 35 airplanes per month in 2012. The rate increase will meet continued strong demand for the Next-Generation 737. The Next-Generation 737 family has more than 2,000 unfilled orders from customers around the world.