While Gurman hasn't shared specific details about the 15-inch MacBook Air, analyst Ross Young previously stated that Apple's suppliers will commence production of 15.5-inch display panels for the new model in the first quarter of 2023. This indicates that the laptop could debut in the first half of the year.

Given the recent redesign of the MacBook Air in 2022, it's likely that the 15-inch model will share a similar design to the latest 13-inch model, featuring options for both M2 and M2 Pro chips.
As for the 12-inch MacBook, Gurman had previously hinted at a potential launch towards the end of 2023 or early 2024. However, in a recent Power On newsletter, he mentioned that this laptop is no longer part of the company's short-term roadmap.
Apple has previously released both budget-friendly and high-end 12-inch laptops. In the budget segment, the company introduced the ultra-thin, sub-1kg MacBook 12-inch in 2015, but production ceased in 2019. In the higher-end segment, Apple offered the PowerBook G4 12-inch in the early 2000s before its discontinuation.
The previous 12-inch MacBook faced criticism due to thermal issues stemming from its Intel processors. However, with Apple's recent transition to using M-series Silicon chips, there's a possibility that the company will reintroduce an ultra-thin MacBook, sans fan. Let's stay tuned for more updates!
