You can now develop AIR 2.5.1 for TV apps for Samsung Smart TVs.
Register at the Samsung D Forum to learn how to package AIR apps for Samsung Smart TVs.
Read this document: AIR for TV Application Guide for Samsung TVs. You will need to login to the Samsung D Forum to read the document, but you can quickly get a login id by following the instructions on the Samsung D Forum page.
You can learn more general information for developing AIR for TV apps at Developing AIR applications for television devices.
More information like samples, tutorials, and articles are at Flash Platform for TV.