What are the differences between MacBook M2, M3, and M4?

Among other websites with that and other info:

• https://www.macrumors.com/guide/m2-vs-m3-vs-m4-macbook-air/
• https://9to5mac.com/2024/05/30/m4-vs-m3-and-m2-apple-silicon/
• https://en.wikipedia.org/wiki/Apple_silicon#M_series_SoCs

More generally:

MacBook Air is the most portable model, but that portability comes at the cost of expandability, ports, and performance.

If you want to use external displays, make sure you check the specs for the particular M-series variant. Lower-end M variants can be limited to two total displays, including the internal.

if you plan to keep any Apple silicon M-series Mac for a while, I would not go below 16 GB memory, and would purchase more internal storage than you think you need.

If you are talking about Macs with plain M2, M3, or M4 chips:

• Mac notebooks with plain M2 chips only have two USB-C (Thunderbolt) ports and can only drive one external display. When they were new, they could be custom-ordered with up to 24 GB of RAM.
• Mac notebooks with plain M3 chips only have two USB-C (Thunderbolt) ports. They can drive one external display with the lid open, two (with limitations) with the lid closed. When they were new, they could be custom-ordered with up to 24 GB of RAM.
• Mac notebooks with plain M4 chips have two USB-C (Thunderbolt) ports (MacBook Air) or three USB-C (Thunderbolt) ports (plain M4 MacBook Pro). They can drive two external displays with the lid open. They can be custom-ordered with up to 32 GB of RAM.

MacBook Pros with plain M2 chips have a 13" chassis that is similar to the MacBook Air one, except that it lacks the MagSafe 3 charging port, and has a Touch Bar. MacBook Pros with plain M3 and M4 chips have a 14" chassis that is similar to the ones for 14" {M3/M4} {Pro/Max} MBPs. The 14" chassis has a mini-LED backlit screen, HDMI port, SDXC card slot, and cooling fans (but no Touch Bar, which has gone the way of the dodo).

M3- and M4-family chips have hardware ray tracing support in the GPU. This potentially could be useful for games, though I do not know offhand, which games use it.

If you are talking about Macs with M2/M3/M4 {Pro/Max} chips, these are generally more capable. See the Technical Specifications for details.

https://www.simplymac.com/macbooks/apple-m-series-chips-explained

The guide to the tech specs in each machine are available on Apple's website here where you can compare each model.

Mac - Compare Models - Apple

The hosts have re-titled your post, which may have changed the question entirely. Are you asking about the differences between those model MacBook Airs or the differences between the processors.