According to the User's Guide of the MacBook Air, it says:
Set up your MacBook Air on a stable work surface that allows for adequate air circulation under and around the computer. Do not operate your MacBook Air on a pillow or other soft material, as the material can block the airflow vents.
The only airflow vents I see are in the back right where the screen and keyboard meet. Thus, I'm wondering if covering the front 90% of the bottom of the MacBook Air with something soft such as a cloth (i.e. the part with no vents) will have any adverse effects on the cooling mechanism. The only thing I can think of is that the bottom of the laptop acts as passive cooling by having that little bit of air between the bottom of the laptop and the desk its sitting on. Having it on a cloth or something similar would no longer provide this air cushion and would affect the cooling mechanism of the laptop.
Is my theory about how the passive cooling works correct? Or is it fine to use the laptop on something such as a pillow as long as it doesn't cover the end that has the vents?