Decompiling Adobe AIR applications

Here is what you are looking for ;) http://www.sothink.com/product/flashdecompiler/index.htm

Sothink SWF Decompiler claimed the file was corrupt.

What worked for me, was JPEXS Free Flash Decompiler which had the added benefit of being open source and completely free. https://github.com/jindrapetrik/jpexs-decompiler/releases

Packaged AIR files (those with .air extension) are ZIP files. You can use any ZIP program to pull them apart.

However, AIR apps can be written in Flash, Flex or HTML/JavaScript. If the app you want to look at is not the latter, you will need a Flash or Flex decompiler.