In the commercial aviation industry, when a new aircraft is introduced to the market, that often means a new engine is being introduced. It is common for new aircraft to be centered around new engines rather than a completely new aircraft design. This has led to more significant innovation in engine design than in aircraft design in recent years. Two aircraft that flaunt new engines today are the Boeing 737 MAX and Airbus A320neo.
A common misconception is that the two aircraft use the same engine. It is not a wholly unjustified misconception, for reasons that will be shown in the following sections, but it is important to distinguish the two. It is important to understand the differences in aircraft design to ensure accurate public debate and discourse. This article will profile each engine and give more context to the comparison between the two.
A Fair Question
The title question of this article is one that comes up often when discussing these two aircraft. And it is easy to understand why. For one, both engines have a number of visual similarities. They are both new, high-bypass turbofan engines that are made by the same producer, CFM. CFM International is a joint venture between American engine manufacturer GE Aerospace and French engine manufacturer Safran. For this reason, both engines are marketed under the LEAP name, which only adds to the confusion. In reality, the A320neo operates with the LEAP-1A engine and the 737 MAX operates with the LEAP-1B.
As mentioned, the assumption that the A320neo and 737 MAX are powered by the same engine is fair for those outside of the aviation community. Both LEAP engines are aimed at fuel efficiency, and serve a similar purpose; they each power a single-aisle aircraft that is an upgraded design from previous variants. All of these shared attributes make the question a fair one to ask.
It is also easy for the media to simplify new engine technology into a single overarching shared technology. While new engines today share some design attributes, each LEAP engine on each of these two aircraft has a distinct design. It is important to understand how each engine on the market today is different, and how engine design can be tailored to a specific aircraft.
A320neo Engine Options
The A320neo family of aircraft was developed from the popular A320 family of narrowbody airliners by Airbus. The first service flight took place on January 25, 2016, with 
Lufthansa. As of November 2025, 4,275 total A320neo aircraft have been built across all variants. Airbus advertises up to 20% lower fuel burn on the A320neo thanks to added sharklets on the wings and two new engine options.
The two engines available on A320neo aircraft are the CFM International LEAP-1A and Pratt & Whitney PW1100G-JM. Both engines contain advanced technology that makes the A320neo much more attractive compared to its predecessors. The PW1100G-JM is a variant made for the A320neo and features a geared turbofan architecture. The LEAP-1A is a non-geared turbofan that uses composite materials, such as ceramics and carbon fiber, in its fan blades to make the engine lighter. The table below compares the two engines.
|
A320neo Engine Options Comparison |
||
|---|---|---|
|
Metric |
CFM LEAP-1A |
PW1100G-JM |
|
Fan diameter (inches) |
78 |
81 |
|
Bypass ratio |
11:1 |
12.5:1 |
|
Length (inches) |
131.0 |
133.9 |
|
Max. width (inches) |
100.1 |
87.6 |
|
Weight (pounds) |
6,631 |
6,300 |
|
Max. thrust (pounds-force) |
32,160 |
33,110 |
Source: CFM, Pratt & Whitney
The true engine option nature of the A320neo is a great benefit to Airlines and operators. While both engines are solid choices, operators may have preferences towards one manufacturer for any number of reasons. This helps the A320neo reach a wider market as airlines have flexibility in how they use it in their fleets.
The 5 Engines That Have Powered Airbus A320-Family Planes
CFM International, IAE and Pratt & Whitney engines have powered the A320 over the decades.
737 MAX Engine
The 737 family of aircraft is one of the most popular line of aircraft ever built by 
Boeing, and perhaps by any manufacturer. The 737 MAX series followed the 737 Next Generation and has been in service since its first flight with Malindo Air in 2017. Many are aware of the two fatal accidents the 737 Max had in 2018 and 2019, which grounded the aircraft in most countries until late 2021. Today, the aircraft is operated by many airlines all over the world and 396 737 MAX aircraft have been delivered across all variants in 2025 through November.
Similar to Airbus, Boeing advertises up to 20% lower fuel burn on the 737 MAX thanks to the new engine technology. However, unlike the A320neo, the 737 MAX only has one engine option that was made specifically for it. The CFM LEAP-1B engine is present on all 737 MAX aircraft, regardless of variant. While similar to the LEAP-1A engine, the LEAP-1B differs slightly due to the unique design of the 737 airframe. The table below highlights some of the LEAP-1B’s design metrics.
|
CFM LEAP-1B Design Overview |
|
|---|---|
|
Fan diameter (inches) |
69.4 |
|
Bypass ratio |
9:1 |
|
Length (inches) |
123.9 |
|
Max. width (inches) |
95.3 |
|
Weight (pounds) |
6,130 |
|
Max. thrust (pounds-force) |
29,320 |
Source: CFM
The LEAP-1B had to be designed to work with the 737 MAX airframe. There were some key constraints that limited the size of the engine. The biggest constraint was ground clearance. The 737 historically sits low to the ground, so any engine needs to have sufficient ground clearance. When designing the 737 MAX, Boeing worked directly with CFM to engineer an engine that worked for the aircraft. The result was the LEAP-1B, which had a reworked nacelle shape and sat more forward and higher on the wing than previous 737 engines. This, in part, is what ultimately led to the unwanted pitch-up behavior that the faulty MCAS system was designed to counteract. Today, the LEAP-1B is the only engine that can be fitted to the 737 MAX.
Why Can’t The Boeing 737 MAX Be Powered By Any Other Engine Type?
Why the 737 MAX uses only the LEAP-1B: Boeing’s design limits, certification rules, and engine geometry make any other powerplant impossible.
Comparing The Two LEAP Engines
CFM developed the two LEAP engines with each aircraft in mind. They come from the same family, which is why they have similar size and performance characteristics. But tailoring the engine to each aircraft is why there are slight differences in characteristics. For a more direct and in-depth comparison between the LEAP-1A and LEAP-1B engines is shown in the table below.
|
LEAP Engine Comparisons |
||
|---|---|---|
|
Metric |
CFM LEAP-1A |
CFM LEAP-1B |
|
Fan diameter (inches) |
78 |
69.4 |
|
Bypass ratio |
11:1 |
9:1 |
|
Overall pressure ratio |
40:1 |
40:1 |
|
Length (inches) |
131.0 |
123.9 |
|
Max. width (inches) |
100.1 |
95.3 |
|
Weight (pounds) |
6,631 |
6,130 |
|
Max. takeoff thrust (pounds-force) |
32,160 |
29,320 |
|
Max. continuous thrust (pounds-force) |
31,690 |
28,690 |
|
Max. rpm |
19,391 |
20,171 |
Source: CFM
Overall, the two engines are fairly similar. The design variances are almost entirely due to the size constraints of the 737 MAX. The result is that the LEAP-1B is smaller and slightly less powerful than the LEAP-1A on the A320neo. The advanced technology in the LEAP engines is part of the reason airlines are deploying the A320neo and 737 MAX on long transatlantic routes by airlines. Notably, 
United Airlines became the first US carrier to offer nonstop flights to Madeira, Portugal, when it launched the seasonal service this past Summer from 
Newark Liberty International Airport on the 737 MAX 8.
Considerations For Airlines
For airlines in the market for a new narrowbody airliner and deciding between the A320neo and 737 MAX, there is a long list of factors to consider. For the purpose of this discussion, let’s focus on the powerplant of each aircraft. A320neo operators have to be cognizant of which engine they choose to fit onto the aircraft. Maintenance philosophies and practices may differ between CFM and Pratt & Whitney engines. This is not a drawback but rather an added consideration with the A320neo. Furthermore, the engine options for the A320neo open other discussions on how each engine profile will fit in the route network. They are similar but will contain different operating costs.
On the other hand, airlines considering the 737 MAX do not have an engine choice. This means the maintenance requirements and infrastructure are known beforehand. However, this also means the airlines need to be certain the LEAP-1B is the right engine for its operations and route strategy. At the end of the day, the engines will most likely not be the end all be all for an airline deciding between these two aircraft, but it is an important comparison nonetheless.
The answer to the question of this article is: no, the 737 MAX and A320neo are not powered by the same engine. While it is true that both aircraft operate with CFM LEAP engines, the distinction lies in the details. The A320neo uses the LEAP-1A engine, and the 737 MAX uses the LEAP-1B engine. These engines come from the same family but are not the same. They differ in size and, as a result, in performance. This represents a common practice of designing an engine for the aircraft, as opposed to the other way around. Understanding the differences between these two engines ultimately highlights how each aircraft is different.
