FARNBOROUGH—Boeing has confirmed plans to revamp the slow-selling 737-7, the smallest of its new re-engined MAX family, by adding extra seats. But the airframer is expressing an increasingly cautious attitude to the possible development of a larger variant of the 737-9 to compete directly with the Airbus A321neo.                                                                       

“We are finalizing the size of the 737-7 and will increase it by two seat rows, or about 12 seats bigger than the 737-700 Next Generation,” said John Wojick, Boeing’s sales and marketing vice president. “People ask ‘Why?’ Because our large customers for the 737 have all voted, including Southwest [Airlines] and WestJet [Airlines], and they wanted an airplane that produced more capability, more range and more seat count than the airplane they both operate today. So we are officially increasing the size of that aircraft.”

The revised design will include a 76-in. longer fuselage to accommodate the additional seat, rows and was unveiled at the show following negotiations with 737-7 launch customers Southwest and WestJet, which will now convert their orders to the revamped configuration. The aircraft will also have additional range and improved hot and high performance.

At the higher capacity end of the MAX market, Boeing Commercial Airplanes President Ray Conner said the outcome of studies of a larger 737 variant, beyond the capacity, of the -9 depends “truly on what the customers are looking for.”

“The MAX 9 is a nice little airplane today that has a lot of range to it, with more range than the A321, and we can do with one [fuel] tank what it takes the A321 to do with three tanks. Our seat-mile costs are lower as a result of that,” he said.

Studies of the larger MAX variant, dubbed “Mad MAX” by John Leahy, Airbus’ chief salesman, have revolved around growth derivatives of the 737-9 configured with a variant of the larger CFM Leap-1 developed for the A320neo and the Comac C919. But the larger MAX design is complicated by the need to raise the main gear to accommodate the bigger engines, potentially adding considerably to development costs.

“We have to make sure there is truly a big enough market segment if we want to move up and that’s where our customers want to go up with the MAX 10. But that MAX 10 still does not address, necessarily, the other market that’s above it,” said Conner, referring to the lower end of the middle-of-the-market, 757-replacement sector.