Just FYI, the Air only comes in 11 and 13 inch models. The MacBook PRO comes in 13, 15, and 17 inch models however. The Air is the sort of netbook of the Apple lineup.
And just to economize posts, I'd reconsider the Air for college use. In fact, I'd reconsider the whole laptop idea completely. Laptops get stolen often, and more than that, they are a distraction in class far more than they are a useful aid. If your daughter has even the slightest of inclination towards websites like Facebook and Twitter, and isn't one of the single most disciplined people you have ever known... Get her a nice iMac or something to keep in the dorm/sorority/apartment. Otherwise, she's going to spend more time on Facebook and the like than paying attention in class, her grades will suffer and either you'll be paying for an extra semester to a year for her to graduate, or she'll be an extra semester to year in debt as far as loans go.
Laptops in college sound like a great idea, but they really almost never work out that way. I eventually had to just start leaving mine at home when I found myself doing other things besides taking notes, and for the most part, I could give a toss about the likes of Facebook and it's ilk. The only thing of moderate interest to me about Facebook, is the HQ is about 20-30 miles down the road from me. That and it's like this bizarre sociological microcosm along the lines of a train wreck. You know it's going to be gruesome, you know you shouldn't look, but you just can't stop.
So get her a nice-ish computer for her dwelling, that stays in her dwelling. I'd even encourage her to do all her homework on campus using lab computers. For one, part of her tuition will be to pay for those, so may as well use them, but also it helps create a psychological association between work and play. When she's on campus, her associations are with work, and when she's off campus, she can focus on her social life. Useful for college life, and useful for life after college.
Also, I doubt a 128GB drive would be big enough for most people, and the fact that it's flash storage PROBABLY wouldn't work so well with a college student. Flash drives don't have the same kind of longevity as platter based drives. Platter based drives typically work until the motor spinning the platters gives out. Flash cells, on flash drives, have a finite number of times you can write to them before they fail. And you can just take the new MacBook Air anywhere to get the drive replaced like other laptops. It's a custom designed drive, and the screws used to lock the bottom case on the new MacBook Air are exceedingly difficult to find if you're not an Apple Authorized Service Provider. I honestly don't know how they will classify drive failures on the new Air models either. It's entirely possible that they will deem them consumables like batteries, and thus not subject to replacement under warranty.