I had dealt with the creaking of my 2011 13" MBA for a few weeks, brought it in twice and had the Geniuses tighten the pentalobe screws and also tightened them myself. The creaking would get slightly better -- but then return with a vengeance. I decided to take it upon myself to fix the issue. The creaking is a result of motion of the base plate relative to the screw heads (and upper case) as the body is stressed. Someone had mentioned in another thread the word "monocoque" -- which is exactly what the MBA is. The base plate is an integral part of the body's rigidity. I decided to try and find some new screws that I could at least tighten without stripping, perhaps some hex or phillips heads. I settled on some stainless M2x0.4mm flat head screws. As it turns out -- the flat head was a good choice, unknowingly. The screws are McMaster-Carr p/n 91801A105. The screws themselves are phillips head, a few mm in length (which were subsequently filed to length and the threads chased with a M2 die). After installing them -- the creaking is completely gone, and the body feels much more rigid. The flat head screws are sort of a "wedge" that self-centers in the hole in the baseplate, and also keeps the plate from shifting relative to the screws. There are a couple of issues, however. First, the screw heads are slightly wider than the recesses in the base plate so the heads don't sit entirely flush with the body. Its not really that noticeable, but you can tell there is a screw head there as opposed to the smooth feel of the stock screws. The second thing is the screws themselves -- perhaps Apple designed the body to flex, and by using these screws I've removed that ability and who knows what the consequences are. Either way -- the creaking is gone and the body feels much more rigid. I love keeping Apple products stock -- I don't use cases at all on any of the products from them that I own. In this case though, I decided the deviation from stock was worth the benefit of no creaking when I am typing on my lap. To each his (or her) own.