Copied from http://www.apple.com/macbookair/design.html

Designing MacBook Air came with one goal: Create an incredibly thin and light notebook computer that’s every bit as powerful and capable as one twice its size. With flash storage, durable unibody construction, Multi-Touch technology, and a long-lasting battery, MacBook Air not only achieves that goal, it sets a new standard for what every notebook should be. Perfected down to the millimeter.

Even at less than an inch thin, MacBook Air sets a pretty high standard — by making flash storage standard. Flash chips are very small, allowing MacBook Air to be incredibly thin and light. Flash is also solid state, meaning there are no moving parts. Which makes it reliable, durable, and quiet. And because we place the flash chips directly on the logic board, they take up much less space — about 90 percent less, in fact. That creates room for other important things, like a bigger battery. So you have a notebook that weighs almost nothing and runs for hours on a single charge. That’s mobility mastered.

Multi-Touch technology is part of practically every Apple product. It’s the best and most personal way to interact with your devices. And the optimal way to experience Multi-Touch on a notebook is through a trackpad. That’s precisely the case with MacBook Air. The trackpad’s spacious, all-glass surface doesn’t have a button because the whole thing is the button. And with new Multi-Touch gestures in OS X Lion, you can interact with MacBook Air in ways that feel more intuitive and realistic than ever before.

Anyone can try to make a notebook that’s thin and light. Success comes in doing it without cutting corners. That’s why MacBook Air features a full-size keyboard, not a condensed version of what you’re used to. When you type on the MacBook Air, it’s just as comfortable as typing on a desktop keyboard. And now the keyboard is backlit, so you can type comfortably even in low-light conditions. A built-in sensor detects changes in the ambient lighting and adjusts the keyboard and display brightness automatically, giving you the perfect illumination in any environment.

If you looked inside MacBook Air, you’d see something remarkable: how much space we devoted to the battery. That’s thanks to smaller components such as flash storage. And when the goal is to design the perfect notebook for everyday use, giving priority to the battery just makes sense. With MacBook Air, you can get up to 5 hours of battery life on the 11-inch model and up to 7 hours on the 13-inch model. Put MacBook Air to sleep for more than an hour, and it enters what’s called standby mode.* That means you can come back to MacBook Air a day, a week — even up to an entire month later — and it wakes in an instant. Time is on your side, courtesy of MacBook Air.

FaceTime Camera

Make video calls with a built-in FaceTime camera that’s even smaller than the one inside iPhone 4.

MacBook Air features a unibody design for both the main enclosure and the display. Unibody construction means a higher-precision, less complex design with fewer parts. And that translates to a notebook that’s exceptionally thin and light, yet durable enough to handle the rigors of everyday use.