Just read the details that the new MacBook Air has no optical drive. The rationale is that it makes the machine lighter and have longer battery life.
You know what I think? If you have an optical drive, you'll buy or rent DVDs when you want to watch a movie on your laptop. If you don't have an optical drive, what do you do? You rent them through iTunes. Kaching!
This explains why the MBA is so reasonably priced. It's a loss leader to Apple's real business - entertainment media distribution. You don't have to be an MBA to figure that one out... :)