Two awesome laptops, the Apple MacBook Air vs MacBook Pro Retina - you may be asking, "which is best for me"? Well, it really depends on how you plan on using it and how heavy a user you are.
MacBook Air: The MacBook Air is the slimmest and lightest laptop Apple offers. It comes in 11" and 13". Both are great for travel obviously and are great for general to medium use. One of our employees regularly uses his MacBook Air to run multiple desktops, a virtual machine and multiple applications simotainously without skipping a beat.
MacBook Pro: The MacBook Pro comes in 13" and 15" sizes and the awesome Retina display is available in both 13" and 15". The MacBook Pros are a little heaver, but by no means a "boat anchor" and even the 15" is pretty easy to travel with. One occasional downside to the 15" MacBook Pro is that is doesn't always fit in some hotel wall safes. The Retina display on the MacBook Pro is incredible and a must have for anyone who appreciates quality. And if you're spending the day looking at your laptop, you'll want the nicer display especially if you're watching the occasional movie. The MacBook Pros also have beefier graphics and processing power and are more inclined for heavier computer users.
For more on the differences comparing the MacBook Air to the MacBook Pro, the following comparisons will be helpful:
MacBook Air Models and Configurations
MacBook Pro Models and Configurations