Not just Keynote Remote. Apple's own "Remote" app for iPhone (free) works very well for controlling iTunes completely.
If you really want to use the Apple Remote (hardware) with the MBA, it can be done, but you need a USB IR dongle for a receiver on the MBA. There are several that do work with Apple Remote and MBA.
Personally, I find the Remote app a much more elegant solution as you can navigate your entire iTunes library, and it shows album/movie covers right on your phone too.