iFixit

Edit Step 17  ¶ 

• MacBook Air 13" Mid 2011 Repairability: 4 out of 10 (10 is easiest to repair).

  • Once you manage to take off the bottom cover, all the parts are pretty easily replaceable.
  • Opening the bottom cover is quite difficult if you don't have the right screwdriver. It's clear that Apple didn't want people to open their machine.
  • All the components -- including RAM and SSD -- are proprietary, meaning that no off-the-shelf parts will work in it without serious rigging.