United Airlines continues to expand as it’s taken delivery of five Boeing 737 MAX 9 jets in just seven days (or in essence, one 737 for every workday). We’re seeing not just aggressive growth on United’s part (which has positioned the 737 MAX front-and-center in its ambitions), but also improvements in production flows from Boeing.
After today’s deliveries, United is beginning to reach a milestone. CH-Aviation shows that United currently has 136 Boeing 737-900ERs in service, the predecessor to the 737 MAX 9. With these new deliveries, the 737 MAX 9 fleet amounts to 111, and with 114 remaining on order, we will soon see the 737 MAX 9 fleet surpass the 737-900ER fleet in size.
United’s Fleet Transition
United has long relied on the 737NG for its operations, in particular, the 737-800 and 737-900ER. In total, United has 141 737-800s in service and 136 737-900ERs flying, along with 12 older 737-900s. With the 737-900s added, this makes for a combined total of 148 737-900s and 737-900ERs currently flying for United Airlines.
What’s intriguing about this is that United’s 737NG fleet came largely from Continental Airlines. Prior to the merger, United relied on the Airbus A319, A320, and Boeing 757-200 for its short-haul operations, while the 737s came from Continental. After the two airlines became one, United ordered more 737s, and then proceeded to order huge numbers of 737 MAX aircraft.
While the 737 MAX 9 fleet is set to overtake the 737-900ER fleet in numbers soon, this isn’t due to changes in the latter’s fleet size. Rather, United is growing the Boeing 737 MAX fleet while the 737NG fleet remains as is. Instead, United is retiring Airbus A320-200s as these are some of the oldest aircraft in its fleet, thereby significantly growing the 737 fleet partially at the expense of the Airbus fleet. Today, more than 50% of United’s fleet is made up of Boeing 737 aircraft.
Looking At The 737 MAX 9’s Role In United’s Fleet
As part of United’s growth strategy, the Chicago-based carrier is upgauging existing routes. This involves displacing aircraft with larger planes on existing routes, and then the smaller airliners either commence new routes or displace even smaller aircraft that then start new routes. While United is retiring some A320s due to age, most new 737 MAX and A321neo deliveries are for growth.
In United’s fleet, the A319 and 737-700 seat 126, while the A320 can carry 150 passengers. The 737-800 and 737 MAX 8 seat 166, while the A321neo seats 200 passengers. While the 737-900ER and 737 MAX 9 are considered “large narrowbodies”, their seating capacity is actually closer to the 737-800/737 MAX 9 at 179 seats. In a way, they essentially slot in between the 737 MAX 8 and Airbus A321neo.
Though it’s not quite as big as the A321neo, the 737 MAX 9 is the largest Boeing narrowbody that can be obtained today. By upgauging 737-800 or A320 flights to the 737 MAX 9, United can grow its overall passenger numbers. The 737 MAX 9 also has a lower overall fuel burn than the A321neo (though the A321neo has lower fuel burn per seat), and it can perform essentially every route in United’s short-haul network.
The 737 MAX 9 and 737 MAX 10
While the growth of United’s 737 MAX 9 fleet is impressive, it was never intended to be the star of the United fleet. Rather, United originally placed most of its eggs in the Boeing 737 MAX 10 basket, initially converting 100 737 MAX 9 orders and then adding additional units. Entry into service (EIS) was expected in 2020, and the 737 MAX 10 was to be United’s principal weapon in growing its domestic capacity to match and overtake its rivals.
Instead, the 737 MAX 10 experienced delay after delay, while United and others waited patiently with little or no jets actually being delivered. EIS for the variant is currently targeted for 2026, and United Airlines has been one of the most vocal critics of the program’s delays. In 2024, CEO Scott Kirby announced that the carrier was removing the 737 MAX 10 from internal planning due to uncertainty about when the plane would be certified.
|
United 737 Fleet |
In Service |
On Order |
Capacity |
|---|---|---|---|
|
Boeing 737-700 |
40 |
126 |
|
|
Boeing 737-800 |
141 |
166 |
|
|
Boeing 737-900 |
12 |
179 |
|
|
Boeing 737-900ER |
136 |
179 |
|
|
Boeing 737 MAX 8 |
123 |
166 |
|
|
Boeing 737 MAX 9 |
111 |
114 |
179 |
|
Boeing 737 MAX 10 |
167 |
189 |
United still needs new planes to meet its growth plans and replace aging A320s, so many 737 MAX 10 orders were converted back to the 737 MAX 9. As it stands, United currently holds 167 orders for this variant, as opposed to the over 200 737 MAX 9s that it is expected to one day operate. This will also make the 737 MAX 9 the most common variant of the Boeing 737 in United’s fleet.
