For now not.
I started to work on the 4.0 adapter. But it's really really hard to use ExtJS4.0 in Adobe AIR, because ExtJS uses a lot of XTemplates within all components and Function constructors all over the framework. And that doesn't work with the application sandbox concept of Adobe AIR. I already have some workarounds, but every time a new ExtJS version is available, everything changes and I have do adjust and adjust and adjust.
Another point is, that I don't believe ExtJS4.0 to be stable as it is now, although it's named "stable".
A third thing: The draw components don't work with Adobe AIR since AIR doesn't support SVG. I hope, some future version of AIR will do. Adobe had a key role in the development of SVG and AIR is based on a webkit browser, so it's kind of absurd that AIR doesnt support it.
So I'm waiting and hoping for both, ExtJS to be stable enough and Adobe AIR to support SVG.
It is best to use the latest ExtJS3 version with AIR. It's a pity that the ext-air-3.3.2 version of the adapter still isn't available on the download page, although I'm asking for month -> broad hint to @JamieAvins .
I also think about Appcelerator Titanium Desktop as an alternative for ExtJS4. It has pros and cons. Nothing concrete here...
Best regards,
makana
Programming today is a race between software engineers striving to build bigger and better Ń–diot-proof programs, and the universe striving to produce bigger and better idiots. So far, the universe is winning. (Rick Cook)