Apple's latest updates to its MacBook Air laptops have been getting rave reviews for their incredible battery life: the 13-inch model clocks more than 12 hours on a single charge. Unfortunately, these new Airs have also been getting some unwanted attention for a potential Internet connection failure. In particular, numerous users report that their Internet connection drops out within minutes of them getting online. A bit surprisingly, this occurs even though the computer's Wi-Fi connection still shows a normal strong signal.
I first became aware of this matter via a Gizmodo article that provocatively asked: "Is Your New MacBook Air's Wi-Fi Crappy?" The article claims that "a couple of thousand disenfranchised Apple customers seem to have descended on the Apple Support Forums." Given that there were less than 150 posts in the cited Support Communities thread, Gizmodo's claim of "a couple of thousand" complaints seems to be a significant exaggeration. Still, as there are likely many affected users who have not posted their dismay online, the claim is probably true in the larger sense.
Although the new models support 802.11ac Wi-Fi, the problem happens primarily, if not entirely, with older connection technologies. More precisely, the dropped connections appear to occur most often with third-party routers as opposed to Apple AirPort routers, especially routers that are too old to have even 802.11n support. This means that if you take your Air to a Genius Bar at an Apple Store, the Air will likely work fine (as many people have confirmed). This, in turn, means that the Genius will most likely conclude that the problem is in software rather than with the Air's hardware. However, in my view, a hardware cause remains a possibility; it may be one that only gets triggered when connected to certain types of routers.
At this early juncture, there is still no consensus solution. Some users found that switching channels on their router eliminated the drops. Others claimed that deleting one or more files in the SystemConfiguration folder (as described in a 2012 OS X Daily article) solved the problem. Others found that the symptom went away after a complete reinstall of OS X.
As is too often the case, for each of these solutions, other users failed to get the reported success. On the other hand, numerous owners of the latest MacBook Airs have never had this symptom at all.
My guess is that an Apple-supplied software or firmware update will be required to ultimately resolve the matter. In the meantime, if you're planning on buying one of these new machines, be sure to test its internet connectivity right away--so that you have the option to return the machine if it turns out you are a victim of this bug and cannot get any solution to work.