It’s designed to compete against the Airbus A320neo, which made its first flight last year.
Final assembly of the first of the new planes is going on at Boeing’s factory in Renton.
Company executives say it will be ready to fly by early next year.
The new Boeing is designed to use 20 percent less fuel than previous incarnations of the 737.
The key, say engineers, are the winglets — those flanges you see at the tip of the wings. Boeing says the newly designed winglets will offer a 1.8 percent increase in fuel efficiency over previous designs.
“It’s just one of the features that differentiate the 737 MAX and make it an amazingly fuel-efficient machine,” Keith Leverkuhn, Boeing vice president and general manager of the 737 MAX program, told CNN.
Southwest Airlines is scheduled to take delivery of the first batch of new planes in 2017.