Morgan Stanley analyst Katy Huberty provides the latest NPD figures, reports AppleInsider, showing that Apple’s popular MacBook Air now make up 28 percent of the company’s notebook shipments, up from 8% in the first half of this year.

The MacBook Air is rapidly becoming the most popular notebook that Apple offers, which makes a strong statement about the future of the MacBook, as well as the many consumers apparently no longer need an optical drive in their notebooks.

Ever since Apple released new MacBook Airs in July around the release of OS X, the devices have seen a tremendous increase in popularity. The increase is thought to be partially due to the inclusion of Thunderbolt technology, although slimmer, simpler design of the MacBook Air, and its low entry price of just $999 are also significant factors.

MacBook Air users are able to take advantage of many such features using Apple’s Thunderbolt display, which allows the notebooks to connect through FireWire and Gigabit Ethernet, as well as adding additional USB ports.

The MacBook Air’s popularity, combined with Apple’s ever-increasing move away from optical media, have caused many to speculate that future Macs may use the MacBook Air as an inspiration, shedding their optical drives and becoming thinner and lighter.

So, how long before the MacBook Air makes up half of Apple’s notebook shipments? Probably not long at all…