As far as the invisishield goes... It's the best worry-free, no bulk protection you can buy. I love it.
Here's a link to the post - I posted pictures
https://forums.macrumors.com/threads/433784/
I also purchased the Case Logic MacBook 13.3" reversible neoprene cover (whew, that's a long name). It was originally designed for the MacBook, but it fits the MBA real nice. The neoprene material is very stretchy and cushy. Real nice. Make sure you don't buy the regular 13" version of this same line. It was made for regular 13" not the widescreen 13.3", so if you look from the side, it's narrower and taller. I'm sure you guys will get it right, but it could be confusing because if you do a search, it will show both models.
Here's a link to the site. They were having a 20% off sale when I got it.
http://www.caselogic.com/products/index.cfm?modelid=101941&sourceId=CLSHOPNG01
Here are some pics.