Problem: No WiFi connectivity in Lubuntu after installing it on a Macbook Air. I recently installed Lubuntu to breath life into my old Macbook Air 1,1 (2008). The installation went smooth and the operating system is giving me no problems so far.
This one has bitten me every time I have installed either Ubuntu or Lubuntu on a Mac. This post is now the one I refer to each time should I forget the three steps it takes to resolve this problem. Depending on your situation, you may only need two terminal commands and a reboot.