With a glut of "ultrabook" announcements slated at this week's Consumer Electronics Show (CES), Apple watchers have one question: How will the Cupertino company respond?

Backed by Intel, the big PC manufacturers are expected to launch or show ultrabooks, the chipmaker's term for thin, lightweight notebooks that rely on solid-state storage (SSD) in lieu of a traditional platter-based hard disk drive and forgo an optical drive, at CES this week.

According to Intel, more than 75 different ultrabooks will appear during 2012.

But as two analysts who cover Apple noted today, the category isn't new. In fact, Apple was the company that kicked it off.

"They started the ultrabook trend four years ago with the MacBook Air," noted Brian Marshall, an analyst with International Strategy & Investment Group (ISI ), in an interview Monday.

"Apple set the form factor and the bar," agreed Ezra Gottheil of Technology Business Research.

Both experts were referring to the MacBook Air, which Apple introduced in 2008. Sales of the Air, however, took off only after October 2010, when Apple dropped the price and revamped the line to include not only a 13-in. model, but also a lower-priced 11-in. laptop. Four months ago, Apple refreshed the MacBook Air line , equipping the notebooks with faster processors and Mac OS X 10.7, aka Lion.

But Apple's lead in the thin-light laptop class -- last year, it owned an estimated 89% of that market, said Marshall -- is threatened by an expected wave of ultrabooks from big-name PC makers, including Acer, which trotted out its Aspire S5 Monday.

Late last year, Marshall forecast a significant drop during 2012 for Apple's share because of the new competition from Windows-based ultrabooks.

"There will definitely be a lot more attention paid to ultrabooks this week," said Marshall. "And that points out that Apple could be vulnerable here."

So what's Cupertino to do?

Tweak the MacBook Air, said Marshall and Gottheil.

"They can add a little bit more functionality and some more features," said Marshall, ticking off such natural evolutions as higher resolution screens, faster processors and more ports, the latter of which the Air lacks in large numbers.

"Apple can proliferate the Air concept into larger [screen] sizes," said Gottheil, echoing his take last November when rumors of an impending 15-in. MacBook Air began circulating.

"Frankly, it's tough to see how Apple can make the Air all that much better," said Marshall, who called that laptop his favorite Apple product of all time.

Another possible move by Apple, agreed both analysts, would be to reframe the iPad, or at least a version of it, as an ultrabook rival by designing a keyboard and case integrated with the tablet and its iOS operating system.

Third-party vendors, notably Zagg -- which also designed the $99 Bluetooth-based keyboard and case sold by Logitech -- have had limited success with such an accessory.

But Apple should be able to do those designs one better, thought Gottheil.

"Apple hasn't filled the gap that others may exploit with a tablet that also offers a keyboard," said Gottheil, referring to expectations that later this year PC makers will launch devices that function as either a tablet or as a lightweight notebook . "Their little [wireless] keyboard doesn't have a nice carrying case, but I think they will find a way to fill [that gap]."

Gottheil sees Apple tackling the tablet-plus-keyboard issue not as a discrete package but as an add-on, along the lines of the approach it took last year when it launched the Smart Cover accessory for the iPad 2.

But although Apple will face increased competition from ultrabooks this year or next, analysts highlighted the enviable position the company finds itself in.

"It's kind of ironic that it's taken PC OEMs four years to come up with a viable alternative to the MacBook Air," said Marshall.

"If ultrabooks are only thin, light MacBook Air knockoffs, they won't be very successful," chimed in Jack Gold or J. Gold Associates, in an email last week. "They need to be more."