When Apple (NASDAQ: AAPL) launched the 2013 MacBook Air, the response from reviewers and consumers alike seemed overwhelmingly positive. The device's big innovation was in delivering "all day" battery life -- a significant improvement from preceding MacBook Air models.

In 2014, Apple did a minor refresh of these devices to include slightly faster versions of the Intel (NASDAQ: INTC) Haswell processors that the 2013 models used. In early 2015, Apple upgraded the existing MacBook Air designs to include Intel's new Broadwell processors and also significantly sped up the flash storage.

I believe that in early 2016 Apple will bring a more substantial upgrade to its MacBook Air lineup.

New industrial design and a Retina display
In light of the release of Apple's new MacBook, which features a very slim industrial design and a high-resolution Retina display, Apple will almost certainly need to dramatically enhance the next-generation Air.

I'd imagine the next MacBook Air will take a number of cues from the MacBook with respect to the industrial design. Apple is likely to adopt USB-C for refreshed Airs, although I'd expect more than just the single USB-C port found on the MacBook -- maybe a couple?

Additionally, I would anticipate a substantially better display. The low-resolution TN panels on the current MacBook Air models, as I've said repeatedly, are absolutely due for an upgrade.

If Apple wants to contain manufacturing costs, it might forgo the 2304-by-1440 resolution panel found on the MacBook. However, IPS display with a resolution greater than 1440-by-900 for the 13-inch model and 1366-by-768 for the 11-inch model would certainly be welcome.

A new processor, too
According to CPU World, Intel intends to follow the Broadwell-U processors found inside the current MacBook Airs with Skylake-based processors. Intel has said Skylake should improve on Broadwell's performance and power efficiency, so this should free up some of the power budget for the higher-resolution, and almost certainly more power-hungry, display.

When will they launch?
Intel has said Skylake processors will arrive in the second half of 2015. Keep in mind, though, that the chipmaker typically doesn't launch all of the processors in a given family at the same time. According to Fudzilla, which claims to have seen an Intel road map detailing the Skylake launch schedule, the first mobile Skylake chips will arrive in the fourth quarter of 2015.

My guess is that Apple will update its MacBook lineup with the Core M-based Skylake chips that will arrive in late 2015; Skylake should deliver a sufficient performance and power improvement over the Broadwell-based Core M inside the current MacBook to compel Apple to update the machine. 

The 28-watt mobile Skylake chips, which generally share the same silicon as the 15-watt chips with higher-end graphics configurations, are expected to launch in the first quarter of 2016. Since Apple tends to use Intel's highest-end 15-watt chips, the reported Skylake launch schedule points to an early 2016 MacBook Air refresh. 

Keeping the momentum going
I think updated MacBook Airs will offer a large enough improvement over the 2013-2015 models to tempt owners of even relatively recent MacBook Airs to upgrade.

Given that Apple has significantly outgrown the rest of the PC market with its current MacBook Air lineup, it stands to reason that a redesigned device should help Apple sustain its Mac momentum.