With Apples annual Worldwide Developers Conference just months away, its likely were going to see the latest evolution of the MacBook Air appear in June. The 2014 edition of Apples slimmest notebook is expected to catch up to its Pro counterpart with a Retina display and Thunderbolt 2 support, and could add some neat new features like solar charging. Here are all the rumors weve heard so far about the new MacBook Air.