Hi,
I’m looking to get a MacBook Air either 11" or 13" (depending on your advise). I was wondering which would be better for unity. I will be using unity in my i-media college course so I was wonder which one to get and also if a MacBook Air is actually any good.
Thanks 
Your going to get more bang for your buck from a MacBook pro 13" (which is the same price as the 13" macbook air). The air will likely do fine for you but its pretty limited from a CPU standpoint. Graphically… they are both the same. We’ve seen “some” issues on larger projects and the intel chipset where basically Unity will crash from lack of video memory or something (everything just goes white). Outside of processer speed and hard drive space they are really the same for the most part… but i would always go for the larger screen especially if your not running a secondary monitor.
Using Unity on 13" sucks a lot (I have a 13" MacBook Air). I always use a second monitor. I would not recommend the 11", it’s just way too small.
For a while I used an 11in for development. It’s not much fun running Unity in a display that small so I’d usually have a second monitor plugged in. Otherwise it was fine.