You can read here an interesting article about the making of the Slideline AIR application by a team of front-end engineers from Yahoo! Here is a quote from the article about the goals of the project:
* Create a desktop application that allows for the creation, grouping, and auto-execution of advanced search queries against Twitter
* Leverage existing skill-sets and tools
* Target the Windows, Mac OS X, and Linux operating systems and minimize the amount of platform specific code that must be written
* Open source the code so that others can learn from, contribute to, and/or extend the product as they see fit
If you take the time to read the article, you will find some advice about how to approach an AIR project/application. The application is created using HTML/JS/CSS and YUI.