The Boeing 737 MAX program is entering a phase that airlines with major orders have been waiting for years. The two remaining uncertified variants, the smallest 737-7 and the largest 737-10, are now expected to receive approval from the U.S. Federal Aviation Administration by the end of the year. That would finally allow Boeing to close one of the most important outstanding chapters of the MAX program, while giving airlines access to aircraft that have long been central to their fleet renewal and optimization plans.

According to airline executives speaking during the IATA AGM, as reported by Aviation Week, the market is no longer preparing for certification only as a formal milestone, but for the actual entry of these aircraft into service. FAA Administrator Bryan Bedford recently said he expects both remaining MAX variants to be certified by year-end, with the 737-7 expected to gain approval first, followed by the 737-10.

For Southwest Airlines, the launch customer for the 737-7, the smaller MAX variant still has a clearly defined role, although the final balance between smaller and larger aircraft in its fleet may differ from what was originally planned. Southwest built its network for decades around high flight frequencies, particularly in business markets, where smaller aircraft such as the 737-700 played an important role. However, post-pandemic changes in passenger demand, longer average stage lengths and fewer frequencies per route are pushing the airline toward a larger share of 737-8s compared with 737-7s.

Southwest still has a very large number of 737-7s in its order book. According to Aviation Week’s Fleet Discovery database, the airline has 255 737-7s on order, along with 208 737-8s. Chief Operating Officer Andrew Watterson stressed that the basic mission of the 737-7 has not changed, but acknowledged that the final fleet structure could differ from what it might have been without the pandemic. Southwest, he said, has sufficient flexibility in its order book and does not need to make final decisions on the aircraft mix immediately.

That flexibility is also important because of Southwest’s broader transformation. In recent years, the airline has begun introducing changes that would once have been almost unthinkable for its business model, including assigned seating and an extra-legroom product. The company is now openly studying lounges, additional premium options in its domestic fleet and the possibility of transoceanic flights. Watterson emphasized that there is no rush to launch long-haul services, but also that Southwest does not want to fall behind changing customer expectations again.

At the other end of the MAX family is the 737-10, an aircraft that Canada’s WestJet is watching particularly closely. The Calgary-based carrier believes its first aircraft could be delivered by the end of the year if certification expectations are met. WestJet CEO Alexis von Hoensbroech told Aviation Week that the information the airline is receiving from Boeing and the signals coming from the FAA are increasingly converging around certification in the fourth quarter.

WestJet already has six 737-10 aircraft waiting to be delivered, while Boeing’s current delivery schedule begins in December. After FAA certification, the aircraft will also require approval from Transport Canada, but WestJet expects the largest MAX variant to enter commercial service during the first quarter of 2027. According to Fleet Discovery, WestJet has 97 737-10s and 20 737-8s on order.

The arrival of the 737-10 comes as WestJet adjusts its network and capacity. Although the airline also expects 17 737-8 deliveries this year, its overall fleet size is expected to remain broadly flat because of accelerated retirements of older 737-700s. That decision has been influenced by weaker demand between Canada and the U.S., which has not recovered after a roughly 25 percent drop last year, higher fuel prices and the suspension of Canadian airline services to Cuba.

WestJet has not yet set a final retirement date for the 737-700 fleet. The airline had originally expected those aircraft to remain in service until the end of the decade, but that process may now move forward. Still, von Hoensbroech does not expect a rapid removal of all aircraft, partly because most of them are owned and fully written off, giving WestJet useful flexibility in managing capacity.

For Boeing, completing certification of the 737-7 and 737-10 is important for several reasons. Beyond finally completing the MAX family, the manufacturer would be able to begin delivering aircraft that have already been built and are waiting for customers. For airlines such as Southwest and WestJet, this means easier fleet planning, more precise capacity management and the replacement of older-generation 737s with newer, more efficient variants.

However, the market awaiting certification is no longer the same as it was when many of these orders were placed. Southwest is now reassessing the optimal balance between smaller and larger narrowbodies, while WestJet is both rationalizing capacity in weaker markets and expanding its long-term strategy, including growth of its widebody fleet. In late 2025, the airline placed an order for 60 additional 737-10s and seven 787-9s, significantly increasing its future ambitions in both the narrowbody and long-haul segments.

WestJet expects deliveries of the new 787-9s in the early 2030s, after concentrating its widebody fleet in Calgary in recent years and building an international network from that hub. Moves such as these show that the upcoming certification of the MAX 7 and MAX 10 is not viewed merely as a technical event, but as an important trigger for the next phase of network and fleet planning among major users of Boeing’s narrowbody aircraft.

If the FAA’s and Boeing’s expectations are met, the end of the year could mark the beginning of a new stage for the 737 MAX program. After years of delays, the smallest and largest members of the MAX family could finally move from waiting lists into operational service, just as airlines are trying to align legacy orders with a market that has changed more deeply after the pandemic than initially expected.