I have not heard of Sencha coming out with the Air adapter but will ask.
Will wait until then before starting looking at my own solution :)
actually I haven't developed a working AIR adapter for ExtJS 4.0 due to a lack of time during the last months.
I started some work some months ago, but had huge problems using ExtJS 4.0 with AIR.
Look at this post for some discussion regarding this topic: http://www.sencha.com/forum/showthre...ir-VS-Titanium
I've even thought about using Titanium with ExtJS 4.0, but compared with AIR, Titanium misses a lot of features and a good api documentation. AIR's problem is the sandbox concept because ExtJS4.0 uses a lot of XTemplates and so eval calls and Function constructors. And AIR still doesn't support SVG, that is necessary for all the draw components that start with Ext.panel.Panel's rbar/lbar/headerPosition:left or right features and so on.
For now you have to use the latest Air adapter with ExtJS 3.3. ExtJS 3.4 may work but I didn't test it so far.
Well, I have not heard of it coming out with an air adapter but I just hope that they would, and soon. I have been trying to look at some points to possibly be able to get a link for it to work with extjs though I am running out of some resources to complete that task.
^ I hope that you could get some after market support to it so that we could use it rather well.