M2 and M3 chip MacBook Air variants were discontinued in the Apple online store after the new 13 and 15-inch MacBook Air gadgets that feature the M4 chip were introduced.
The M2 was released back in July 2022 while the M3 was released in March last year. It is likely that the gadgets will continue to exist and be purchased via the online Refurbished store Apple has.

The M4 made its first appearance with the iPad Pro in 2024 which was equipped with the chip. The MacBook Air M4 is significantly faster compared to the MacBook Air models that are Intel-based and can support 2 displays externally when the lid is open.
The price for the MacBook Air M4 begins at $999 with pre-orders currently available, followed by its release on March 12, Wednesday.