Computer manufacturers generally update their notebook lines every few months — except for Apple. At best Apple updates their notebook lines twice a year and even longer for the MacBook Air, which received its last major update in mid-2009. Even that was just a processor and battery bump as the storage, graphics, screen, and memory were carried over from the late-2008 refresh.
The latest rumor states the Air will shrink down to a 11.6 display from its current 13.3-inch size and also receive a low-voltage Core processor in the second half of 2010. A new GPU is also in order to work with the latest CPU and chances are the Air will get a higher capacity SSD option.
This model is said to be even thinner and lighter than the current model, which seems about right. Nearly every manufacturer has a notebook whose design was clearly influenced by the Air. Thin notebooks are everywhere now and Apple will likely do what they do best and one-up the competition with the next refresh — whenever that happens.