Southwest Airlines (WN) stands out not only for having the fourth-largest mainline fleet in the world (around 810 aircraft), but it also has the world’s largest Boeing 737 family fleet. The Boeing 737 fleet is the world’s largest MAX-generation fleet (all MAX 8s). The MAX 8 is Boeing’s mid-sized Boeing 737 MAX family aircraft with an advertised range of 3,500 nautical miles, up from the 737-800’s advertised 2,935 nautical mile range.

It is designed to have a typical 2-class seating capacity of 162 to 178 and a maximum capacity of 210 (MAX 8-200 at max theoretical certifiable seats). Like other MAX aircraft, it is exclusively powered by the CFM International LEAP-1B engine. It has a length of 129 feet and eight inches (39.5 meters), placing it between the MAX 7’s 116 feet and eight inches (35.6 meters) and the MAX 10s’ 143 feet and eight inches (43.8 meters) lengths. Here is what to know about the largest MAX 8 fleet in the world.

Southwest: The Boeing 737 Giant

It is common for low-cost airlines to operate all-Boeing 737 or all-Airbus A320 narrowbody fleets, but what sets Southwest apart is the sheer size of its fleet. The Boeing 737 NG and MAX generations come with multiple variants, but Southwest doesn’t even operate all of them. With Next Generation 737s, Southwest only acquired the short 737-700 and standard 737–800 variants and chose not to purchase the extra small 737-600 or the extra-stretched Boeing 737-900/-900ER.

This has continued with the MAX generation, with Southwest satisfied to operate just two MAX subvariants of the four built. Boeing is replacing the 737-700 with the MAX 7, the 737-800 with the MAX 8, and the 737-900 with the MAX 8. There is no replacement for the unpopular 737-600; the fourth subvariant is the even more stretched MAX 10. The MAX 10 has no Next Generation analogue.

Southwest has only placed orders for the MAX 7 and MAX 8 to directly replace its 737-700s and 737-800s and hasn’t ordered the MAX 9 or MAX 10. Only the MAX 8 and MAX 9 had their type certificates at the time of the twin MAX crashes in 2018 and 2019. Since then, the FAA has refused to issue type certificates for the MAX 7 and MAX 10, with the expected date now pushed back to 2026. For now, the MAX 8 is the only next-generation 737 Southwest has received.

Southwest’s MAX 8 Fleet

According to data provided by Ch-aviation, Southwest has 274 Boeing MAX 7s on order but none in inventory. It has 311 Boeing 737-700s in inventory, of which 292 are active, and 19 are inactive. Its Boeing 737-800 fleet now comprises 201 aircraft, of which 183 are active, and 18 are inactive. The MAX 8 fleet is 300 in inventory, of which 297 are active, and three are inactive, with another 181 on order.

The average age of its 737-700 fleet is now 19.7 years old, much older than its 737-800 fleet, which only averages 10.4 years. The Boeing 737 MAX 8 fleet is very new, at just 3.5 years on average. As of the time of writing (January 25), data from Planespotters.net shows Southwest has received one MAX 8 so far in 2026 (registered N8991S).

Boeing’s records show it delivered a total of 55 MAX 8 aircraft to Southwest in 2025, up from 22 in 2024 and down from the 86 Southwest received in 2023. All of these aircraft are delivered with the exclusive CFM International LEAP-1A engines. While Ch-aviation lists Southwest as having 201 MAX 8s in service, Boeing’s records show it has delivered a total of 204 over the lifetime of the program, excluding any delivered in the first weeks of 2026.

Hawaii Dominates Most Frequent Routes

According to data provided by Cirium, when it comes to the most frequent routes for Southwest’s MAX 8s in 2026, Hawaii dominates. About eight of the nine most frequented routes are between the Hawaiian islands. The top route is from Honolulu to Kahului, Maui, with a total of 2,145 flights planned in each direction. These interisland routes are short hops, with this flight averaging just 101 miles.

The next most frequent route is on the mainland between Phoenix and Denver, with 1,457 flights at an average of 602 miles. Following that is the Honolulu to Hilo route with 1,370 MAX 8 flights scheduled for 2026 each way. The route averages 216 miles. Then there’s the Honolulu to Kona route at an average of 163 miles with 1,326 flights scheduled using Southwest’s MAX 8s. Finally, Southwest’s Honolulu route to Lihue, Kauai has an identical 1,326 flights scheduled (102 miles).

All of these Hawaiian MAX 8 routes have the same number of return flights, and all are through the Honolulu hub. Hawaiian Airlines leads with market share at Honolulu Airport with 47%, followed by Southwest at 17%, United at 15%, Delta at 9%, and Alaska at 6%. Of these airlines, only Hawaiian and Southwest compete on the interisland Hawaiian market in a big way, with United, Delta, and Alaska focusing on connecting it with the Mainland or international destinations.

Other Busy MAX 8 Routes

All the other Southwest MAX 8 routes scheduled for 2026 with frequencies above 1,000 flights (each direction) are on the US mainland. Note that while interisland routes on Hawaii have the same number of return flights, this is not the case for mainland flights. There is a heavy emphasis on Las Vegas and Dallas Love Field. After Hawaii, the busiest is Orlando to Baltimore (1,321 flights), followed by Las Vegas to Dallas Love Field (1,291 flights).

Next are Las Vegas to Sacramento (1,179 flights), Denver to Phoenix (1,155 flights), Denver to Dallas Love Field (1,135 flights), and Baltimore to Orlando (1,116 flights). The two longest high-frequency MAX 8 routes are both from Chicago Midway to Phoenix and Las Vegas at 1,444 miles and 1,521 miles, respectively. The shortest Southwest MAX 8 mainland high-frequency route is from Dallas Love Field to Houston Hobby at 239 miles.

The routes with frequencies between 1,000 and 1,099 are Las Vegas to Denver, Phoenix to Las Vegas, Chicago Midway to Phoenix, Chicago Midway to Las Vegas, Orlando to Dallas Love Field, Las Vegas to San Jose, Las Vegas to San Diego, Dallas Love Field to Houston Hobby, and Dallas Love Field to Las Vegas.

Other Large Boeing MAX Operators

Boeing doesn’t break down the MAX by subvariant, but other top MAX family operators are United Airlines, Ryanair, American Airlines, Alaska Airlines, flydubai, Air India, TUI Group, and Air Canada. Ryanair and Alaska are the two other large airlines that exclusively operate Boeing 737 family aircraft, discounting the Boeing 787’s Alaska Airlines is now receiving from Hawaiian Airlines and the A320s operated by Ryanair’s Lauda Europe subsidiary.

Discounting subsidies, Ryanair’s mainline fleet range is even narrower than Southwest’s as it has only purchased the 737-800 and the next generation MAX 8 (specifically the MAX 8-200 sub-subvariant). This is to change, as, unlike Southwest, Ryanair has ordered the stretched MAX 10. Ryanair is the largest airline in Europe and is often seen as the gold standard for ultra-low-cost airlines.

Alaska Airlines operates a broad cross-section of the Boeing 737 family with Boeing 737-700s, 737-800s, 737-900ERs, MAX 8s, and MAX 9s in service and MAX 10s on order. While Ryanair is a true ultra-low-cost carrier, Southwest has been seen as a hybrid carrier, though it’s trending toward a low-cost carrier, at least in some respects, such as dropping its perk of allowing bags to fly for free. Alaska Airlines is seen as trending from being a low-cost carrier to a hybrid carrier functioning more like a major carrier.

Boeing 737s Favored By Older Low-Cost Carriers

Globally, there is a trend for newly-established low-cost carriers to base their fleets on the A320 family instead of the Boeing 737. One of the key ways that airlines keep costs down is by simplifying training, maintenance, etc., and only operating a particular family or even a subvariant of a family of narrowbody aircraft. Once an airline has chosen a family (typically A320 or 737), it is difficult to switch, although it can be done.

Today, older low-cost carriers predominantly use Boeing 737s, and new low-cost carriers established since 2000, and especially since 2010, are more likely to have A320 fleets. Examples of A320-focused low-cost airlines include Wizz Air (established 2004), eastJet (established 1995, later expanded), IndiGo (2006), Vueling (2004), Volaris (2006), JetSMART (2016), Frontier (after its restructuring), and others.

The Boeing 737 had the advantage of being first (1960s), giving it a deeper secondary market and more trained crews. However, as the A320 (introduced in the 1980s) gained traction, that has shifted. Newer airlines, free of the sunk costs of older airlines, have tended to favor the A320. That said, it’s not all against the 737; flydubai was founded in 2008 and has an all-737 fleet, although most of its aircraft on order are A320s. Allegiant started with an all-A320 fleet, but is now purchasing 737s.