DigiTimes heard rumors that a new 12" MacBook Air will enter mass production in the third quarter. This unit will fill the gap between Apple's 11" and 13" MacBook Air laptops. The new model will reportedly be manufactured by Quanta Computer. Not a lot of details are available about the 12" version but some market watchers believe it will have a Retina display.
The sources pointed out that Apple is releasing a 12-inch MacBook Air because its 11-inch model has a screen size similar to its iPad series products and iPad's increasing sales are impacting MacBook demand and therefore the company is looking to establish a clear boundary between the two product lines.
As for when Apple may stop producing the 11-inch MacBook Air, the sources pointed out that the company so far still has not yet set plans to adjust the 11-inch model, but phasing out the device is a logical plan for the long term.