If you want to save yourself a trip to a nearby Apple Store only to be disappointed because they didn't have the exact model of iPad Air you wanted in stock, you'll want to point your favorite Web browser to Apple-Tracker.com's new iPad Air search tool.
It's very easy to use: just select the color and carrier you desire, type in your zip code, and press the big blue button. Within seconds, you'll see with a glance if your local Apple Store has that specific model available, and in what storage capacities. A green box with white checkmark indicates that it's currently available, while a red box with a black X says that you'll need to wait a while.
At this point, the tool seems to indicate that the 128 GB iPad Air models are in short supply at many Apple Stores across the USA. However, if you're willing to drive a bit to get to another nearby store you might just get that "loaded" iPad Air you're dreaming of.