A new Apple Knowledge Base article says:
Some MacBook Air (Mid 2013) computers may encounter an issue that, in rare instances, may cause an intermittent loss in wireless connectivity. The Wi-Fi menu bar icon may or may not indicate that a wireless connection still exists.
Install MacBook Air (Mid 2013) Software Update 1.0 by running Software Update, or by downloading the update directly.
For more information, visit:
2013 MacBook Air Problems? Apple Fixes the Lot
FairerPlatform comments that new products invariably [we would say 'often' - Ed.0\] exhibit some problems and the 2013 MacBook Air is no exception intermittent wi-fi, Photoshop flickering and audio volume fluctuations. What is a little unusual is that Apple has issued an update that nips all three issues, one hopes, in the bud.
They note that developer seeds of OS X 10.8.5 also include a fix for the Photoshop flickering issue in the 2013 MacBook Air, and that installation of the MacBook Air (Mid 2013) Software Update 1.0 requires OS X 10.8.4 build version 12E3067, so, if youre running OS X Mavericks beta, you might want to pass on this patch.
No More CrapBook Air: Apple Issues Update For Spotty Wi-Fi
The Register’s Jasper Hamill notes that theoretically inclusion of the new 802.11ac wireless networking standard in Apple’s mid-2013 Macbook Airs should’ve tripled speeds available to when compared to the older 802.11n protocol used in older models.
However, the integrated adapter on the new Macbook Air ended up performing much more slowly when it came to actually moving files over a wireless connection, and the new update should make people feel a lot better about the wireless connection on their Macbook Air.