In mid-May it was rumoured that Apple was preparing to recieve shipments of ThunderBolt equipped MacBook Airs for release in June or July, both CNET and DigiTimes indicated from their sources that the units would begin filling the supply chain "in late May".
As noted the new MacBook Airs are rumoured to include ThunderBolt connectivity which was first introduced with the MacBook Pro refresh earlier this year, Apple is also expected to move the ultra-portable notebooks to Intel's Sandy Bridge platform.
Now retail sources have suggested to 9 to 5 Mac that supplies of the MacBook Air are becoming constrained around the world, a sure sign of Apple preparing to fill the supply chain with new models.
On Monday, June 6 Apple will kick off its annual WorldWide Developers Conference in San Francisco. WWDC 2011 will run from June 6-10 and the opening keynote will be hosted by Apple CEO Steve Jobs. The company has already outlined that it will discuss iOS 5, iCloud and Mac OS X Lion. A MacBook Air refresh could be quietly slipped into the announcements during the day.