The first generation 13.3-inch model was touted as the world's thinnest notebook. It featured a custom 1.6 GHz (L7500) or 1.8 GHz (L7700) Intel Core 2 Duo processor with 4 MB on-chip L2 cache, Intel GMA X3100 graphics, 2 GB of 667 MHz DDR2 SDRAM, a 80 GB 4200-rpm 1.8-inch PATA HDD or 64GB SSD, and ran Mac OS X 10.7 Lion. To achieve its level of compactness, Apple had to drop the disc drive, FireWire port, Ethernet port, line-in, media card slot, and security slot. This left the notebook with just a single USB port, micro-DVI, and audio out.
The end result was a compact three pound notebook that Jobs famously pulled out of a manila envelope. It tapered from 0.76 inches thick to just 0.16 inches. Although, it suffered from performance issues to start, the MacBook Air played a pivotal role in the transition away from the optical drive.
You can rewatch the MacBook Air's unveiling in the video below, starting at around the 49 minute mark!