AIR stands for, the Adobe Integrated Runtime (AIR) and is one of the latest interesting development from Adobe.
AIR runs on Windows, Mac OS X and a very usable Beta version for Linux. A version for mobile devices is on the roadmap and should be announced in the second half of 2008. It installs the first time you download and run an AIR application, much in the same way that Flash is installed on a computer if the user visits a web site using Flash and they don’t already have it installed.
Air applications run on the desktop and are half way between web based applications (which run in a browser) and full blown desktop applications such as Word or Photoshop.