Like anytime you buy one it depends on what you want to do with it. We need more info than just study on it. We need to know if u need it to be portable, what programs u plan to use ect.
Yup, get yourself an 11'' MBA. Easy to tote to class, good power for casual use. Possibly look at a refurb to save money. You can connect to a larger monitor in your dorm (or w/e) when you need a better screen.
Now if you post more about what you plan to do with it, what budget you have, etc. my suggestion might change
They are both great laptops: blazing fast, battery last long certainly on the 13" MacBook Air. An advantage for the Pro is that it has a Retina Display but the MacBook Air should get in the next version (around March/April)
Top end MBA 11", and NEVER look back, you will own the LAST of the Best\Smallest full functioning laptop EVER, when they kill it, the run will be over, and other than refurbs, there will NEVER be any more, buy new, and NEVER look back, GO FOR IT