Interesting.
Had thought Apple has not changed the Air since it was introduced.
Had to think about it a bit whether I like the old or the new... and decided I like the change. The old looks thinner, slicker but the truth is, the new is more "friendly" to hold. I feel weird holding an iPad like am afraid am going to cut myself. With the new Air, I notice I hold it by its square edges, never the sharp lip.
Then the old had a grey hinge, new black one-piece hinge more stealthy. Old bezel has two hole next to the camera (for?) new one cleaner.