Boeing 737 MAX 9

Updated: October 2026 – A 737 taxis by, the engines have serrated trailing edges, and at the wingtips one winglet points up and one points down – so a 737 MAX. But somehow the fuselage looks longer than usual, and behind the wing there is a door outline you do not know from the MAX 8. Quite possibly you are looking at a Boeing 737 MAX 9. This page shows you how to reliably tell it apart from the MAX 8, 737-900ER and Ryanair’s 737-8200, and where to find this type, which is fairly rare in Europe, in the first place.

What is the Boeing 737 MAX 9?

The 737 MAX 9 is the stretched variant of the 737 MAX, the fourth generation of Boeing’s bestselling narrowbody jet. It replaces the 737-900ER and sits in the family between the widespread 737 MAX 8 and the even longer MAX 10. Boeing quotes typically 175 to 195 seats in two classes for it, and a maximum of 220 passengers is certified. According to the manufacturer, the range is up to around 6,110 kilometers – enough for medium-haul routes and even some routes across the Atlantic.

Every MAX 9 is powered by two CFM International LEAP-1B engines. As with the entire MAX family, there is no alternative engine. Compared with the predecessor, the engines are larger, more fuel-efficient and sit farther forward and higher under the wing, because the 737 traditionally sits very low to the ground.

The first flight took place on April 13, 2017: the aircraft took off from Renton near Seattle, where Boeing final-assembles the 737, and landed at Boeing Field after just under three hours. In March 2018, Indonesia’s Lion Air Group took over the first MAX 9 as launch customer; it was operated by its subsidiary Thai Lion Air. You can find more about the manufacturer and its history on the Boeing page.

The three features that are enough to identify it

With the MAX 9, it takes two steps: first you establish that it is a MAX, then what length it has. Three observations are enough.

The door outline is the strongest single clue but not conclusive: Ryanair’s 737-8200 variant also has additional exits there (more on that shortly). So always watch the ratio of fuselage to wing as well. On the MAX 9, the wing visually sits farther toward the middle of the fuselage, with plenty of fuselage extending at the front and back. In the end, the registration confirms the type – how to read it is covered in the article Understanding aircraft registrations.

Emergency exit or door plug?

Behind the wing, the MAX 9 has a fuselage cutout for an additional emergency exit on each side. How many exits an aircraft needs depends on the seat count. Airlines that install many seats use the exit as a real door. Those who fit the cabin more generously do not need it and have a permanently installed cover inserted instead, the so-called door plug. That applied, among others, to the MAX 9s of United and Alaska Airlines.

From the outside, both solutions look similar: you see a door outline with a window. For identifying the type that does not matter – what matters is that the outline is there at all.

The plug became widely known through January 5, 2024: on Alaska Airlines Flight 1282, such a plug came off shortly after takeoff in Portland (Oregon), and the cabin suddenly lost pressure. The aircraft returned to Portland and landed safely. The next day, the US Federal Aviation Administration (FAA) temporarily grounded all MAX 9s with this plug – around 171 aircraft worldwide according to the agency. After inspections, the affected aircraft returned to service from late January 2024. The US accident investigators of the NTSB found that the bolts that hold the plug in position were missing. Airlines whose MAX 9s have an active door at this spot were not affected by the grounding.

Separately from that, the entire 737 MAX family had already been grounded worldwide from March 2019 (until November 2020 in the US), after two crashes of the MAX 8. The MAX 9 was affected by this grounding just the same.

MAX 9, MAX 8, 737-900ER or 737-8200?

Most mix-ups happen within the 737 family. The table shows the most important differences.

Feature	737 MAX 8	737 MAX 9	737-900ER
ICAO type code	B38M	B39M	B739
Length	approx. 39.5 m	approx. 42.1 m	approx. 42.1 m
Engine	LEAP-1B	LEAP-1B	CFM56-7B
Nacelle trailing edge	serrated	serrated	smooth
Wingtip	split MAX winglet	split MAX winglet	Blended or Split Scimitar
Door outline behind the wing	no (exception 737-8200)	yes	yes

The 737-900ER is the predecessor and practically the same length. Here the engines help you: smooth nacelles without chevrons, plus classic winglets. You can find more on the 737-900ER page.

The 737-8200 is a high-density version of the MAX 8 for around 200 seats, known mainly from Ryanair. Because of the higher seat count, it also has additional exits behind the wing. But it is only as long as a MAX 8 – the wing sits visibly farther back in the fuselage, and the section between the extra door and the tail is short. In a Ryanair livery, a MAX with an extra door is therefore almost always an 8200, not a MAX 9.

The MAX 10 (B3XM) is another 1.6 m longer than the MAX 9 and has a special main landing gear that lengthens somewhat at liftoff. At the end of 2025 it was not yet certified; it is best to check its current certification and delivery status yourself.

Against the direct Airbus rival, the A321neo, the classic Airbus-Boeing check helps: the 737 has the more pointed nose, the dorsal fin in front of the vertical stabilizer and wheels visible in the fuselage in overflight. How to tell the two manufacturers apart in general is explained in the article Telling Airbus and Boeing apart.

Where to find the 737 MAX 9

The MAX 9 is not a mass-market type. By far the most aircraft fly in the Americas: United Airlines and Alaska Airlines together operated the majority of the worldwide fleet in early 2024, and Copa Airlines from Panama and Aeroméxico, among others, come on top. The launch customer was the Lion Air Group, but only a few examples fly there.

In the European and Middle Eastern region, the type is considerably rarer. Small MAX 9 fleets of just a few aircraft each were most recently operated by Turkish Airlines, flydubai and Icelandair, among others, each alongside other 737 variants. We are not aware of a German, Austrian or Swiss airline with its own MAX 9. Fleet sizes and routes change with every schedule, so we deliberately do not name fixed routes here.

Location	Chance of a hit	Why
Major hubs like Frankfurt, Munich, Zurich	low to medium	Foreign airlines with mixed 737 fleets, deployment changes
Istanbul, Dubai	low to medium	Home of Turkish Airlines and flydubai, both with only a few MAX 9s
US hubs of United and Alaska	high	Largest MAX 9 fleets worldwide
Smaller regional airports in Germany, Austria and Switzerland	very low	At most ferry flights or substitute deployments

How to follow flights live and filter by type codes is shown in the guide to Flight tracking with ADS-B. What is behind codes like B39M is explained in the article IATA and ICAO codes explained.

Spotting strategy for a rare type

Because the MAX 9 only shows up occasionally in Germany, Austria and Switzerland, a targeted approach beats chance. At Frankfurt Airport, the Zeppelinheim viewing platform is a proven spot for landings, in Munich the visitors’ hill and in Zurich observation deck B. At all three airports, foreign airlines with mixed 737 fleets land regularly.

What matters is the direction from which the aircraft comes. That depends on the runway direction in use, which in turn is determined by the wind. How to estimate it in advance is covered in the article Understanding the runway direction in use at an airport. You can find more strategies for types that do not come every day under Spotting rare aircraft.

Whether your vantage point is legally unproblematic is answered by the article Is plane spotting allowed?.

Photo tips specifically for the MAX 9

The MAX 9 is a long, slim subject. So that the picture also shows that it is not a MAX 8, you deliberately capture the typical details.

When the light suits your spot, you can calculate in advance; how that works is explained in the guide Planning the sun position for your photo spot. Which equipment makes sense is covered in the plane spotting gear checklist. And if you want to practice type identification in general, Recognizing aircraft types for beginners helps.

Common mix-ups and how to rule them out

Conclusion

The 737 MAX 9 is one of those types you only recognize at second glance – and that is exactly what makes it appealing for spotters. Chevrons and the split winglet give away the MAX family, the door outline behind the wing and the long rear fuselage give away the variant, and the registration provides confirmation. In Germany, Austria and Switzerland it remains an occasional find that you can plan for deliberately with schedules, tracking and a bit of patience.