Do I need to sign a redistribution license to deploy AIR in an enterprise setting ?

At least someone has given a clear answer to the  question about the redistribution license of AIR application in an enterprise setting from a centralized server. Oliver Goldman wrote a clear post talking about the AIR's enterprise support where he pointed out what you can  do in AIR 1.0:

• You can deploy AIR and AIR-based applications via enterprise deployment tools like Microsoft SMS and IBM Tivoli,
  
• You can disable auto-update of both AIR and AIR-based applications, and
  
• You can configure which applications, if any, AIR will permit to be installed.

So the end of the story is that if you're not using the Adobe's download servers fr deploying AIR applications but  your enterprise AIR  is deploying  from an internal server (IBM Tivoli, Microsoft SMS)  that means that you're redistributing  it.

Have also a look at the AIR Runtime Distribution FAQ.