Can't tell if you are serious. Who uses AIR? I've never seen it.

Grooveshark's desktop app used it. Only place I've personally seen it in the wild.

Simfy (another Spotify competitor) also uses it.

http://www.balsamiq.com is a popular software among people doing wireframes. The Desktop version is based on AIR (and it's the only reason why I've installed AIR on my Mac).

BBC use it for their iPlayer app (well hidden though) so I imagine the UK installation base of Air to be pretty large in comparison to other regions.

Certain Twitter clients. That seems to be about it. :)

(It's sometimes used for in-house stuff, but then what isn't?)

League of Legends still uses AIR I believe.

tweetdeck was hugely popular and written with AIR, but I believe they went native some time ago.

Native on Mac & Windows, Chrome-only for Linux (which just isn't the same experience as AIR offered)