You need an ANE. A quick search and there's not one already. Alongside C++ and Java APIs they've created an interface for Unity, so an ANE for AIR should be possible.
I don't know if a third party ANE developer would be interested, it seems a bit niche. It seems more likely Vuforia might create one, being more familiar with their API and as creating it would further grow their platform. It might be a bit niche for them too, but there's no harm in asking. Or you could create an ANE yourself, based on their public APIs.