Yep that's right, the SSD Air's have either 128GB or 256GB. That's easily enough to work with but nowhere near the capacity of spinny disks
Most people nowadays keep just what they need on the laptops and then keep the data on a Networked drive and of course increasingly in the cloud so they can get to it from anywhere.
It'll be interesting to see what they do with the rumoured 15" thinner pro. They could go SSD, or even SSD+hard drive for the best of both worlds though that increases cost and weight.