The 737 series is a family of twin-engine, narrowbody commercial transports. Seating capacity varies depending on model, though the most typical two-class configurations accommodate 126 passengers for the , 162 for the -800, and 180 for the -900ER. All three models, which are the current production versions, are powered by two -7B turbofans. The first 737 flew in April 1967 and received certification in December 1967. The 737 competes directly with the family as well as the . In response to the A320NEO family, in August 2011 launched the 737 MAX, a reengined line of 737s. 's has been selected as the engine for the -7, -8 and -9 versions of the 737 MAX. Rollout of the MAX is expected in 2015 and entry into service is targeted for 2017. Boeing produced 7,010 737s through 2011 and is projected to manufacture 4,799 737s during the 2012-21 period.