According to the Apple guidelines, data that can be downloaded again or regenerated shall be stored in the <APPLICATION_HOME>/Library/Caches directory. So, with AIR 3.6, a new static property, File.cacheDirectory has been introduced, which points to this directory. Files stored in this directory are not backed up on the iCloud. Examples of files you should put in the Caches directory include database cache files and downloadable content, such as that used by magazine, newspaper, and map applications. On Mac OSX and Android, File.cacheDirectory points to the Caches directory ( <APPLICATION_HOME>/Library/Caches on Mac and <APPLICATION_HOME>/caches directory on Android). While on Windows, it points to the parent directory being used by File.createTempDirectory.
var myCacheFile: File = File.cacheDirectory.resolvePath("cacheFile.txt");