Do you not expect to use your computer for any school work at all? If not, your college career will be brief.
What are you thinking of studying, if anything?
The Air is not upgradeable. You can't add RAM or a bigger hard drive as you can (easily) with a Pro. The Air's greater portability comes at the expense of a probably shorter useful lifespan, as the storage and memory demands of the user and of future OS and application software increase beyond what it offers today.
Actually the Air's are much slower then the Pro models. They use a lower powered CPU and can not be upgraded.
So you don't use the DVD drive. You can take that out and replace it with another hard drive. You can also install your own SSD in the main drive bay and move the hard drive to the optical bay. Can't do that with the Air.
IMHO the Air models are like NetBooks. If all you are going to do with it is web browsing and emailing they are fine, but not as good as a good Smart Phone, but if you are going to do any REAL computing there are better options.
Consider an early 2011 MacBook Pro that is being steeply discounted while quantities last from http://www.macmall.com (http://www.macmall.com/n/Blowout-Deals/macCustomPages-175). Use the money you save to upgrade the RAM to 8GB and you'll be set for most, if not all, of your college career. Also, be sure to check out student discounts for AppleCare.
BTW, you can get 8GB of RAM from for your MacBook Pro from a number on on-line sources (www.newegg.com, www.amazon.com, www.crucial.com) for $46US or less. If you feel comfortable installing it yourself (there are instructions in the owner's manual) you can save a lot of money. However, if you don't feel comfortable, you can get it installed by MacMall when you purchase it. It should cost only $99US installed (http://www.macmall.com/p/Axiom-Memory-Solutions-DIMM-Memory/product~dpno~8185432 ~pdp.gcbcdhf), but they may try to upsell you. You can negotiate--DO NOT pay $400! Worst case, buy the RAM for $46 and take it to a shop like Staples, Office Depot, Best Buy, etc. and have them install it.
Take a hard look at the MacBook Air the weight and just overall ease of use is outstanding. With an external monitor and keyboard you will be set when back in your room. More and more items will be stored on a "Cloud" so 128G SSD is not a bad option, if you can afford, go to the 256G SSD.
Either is a great machine, I currently have a MacBook Pro, but am getting tried of the extra weight, thinking of moving over to the Air as described above.