The Macbook Air is not exactly due for an upgrade if you look at the history of Apple's refresh cycle for Macbooks (over two years actually went by between the first and second generation of Airs). The current model was released just last October. But a lot has happened between now and then, namely the introduction of brand new Macbook Pros and iMacs with superfast Intel Sandy Bridge processors and Thunderbolt ports. Since Apple is known to have a soft spot for the super slim laptop line that it calls "The next generation of Macbooks," it's not inconceivable that the company would want to give the Airs (still shipping with the same processor that the original had in 2008, btw) a refresh.
Digitimes is reporting today that such a refresh is scheduled for this June or July. Citing tips from Apple's supply chain partners, the well-sourced Taiwanese tech site says the new Airs will get a largely internal upgrade much in the same way the Macbook Pros did. The new models will get the latest Intel processors and Thunderbolt ports. Good news for people who like absurdly skinny pretty things.