I have just been to an authorized reseller in Phnom Penh (iOne). They had removed all the Airs, and of course I asked why. They said they were preparing for the launch of the new model. I asked if it was arriving tomorrow and the salesman just started smiling. So it seems pretty sure to me that it will indeed arrive tomorrow.
I'm not familiar with how stores go about with the update, but would the reseller employee know about the new MBA release date? It seems like Apple store employees don't know anything as of now.