As they did with the recent iPhone launch, Apple plans on opening their retail stores at 8 a.m. on launch day, November 1, to begin selling the iPad Air. The iPad mini with Retina display is coming later in the month.
This text is from the Apple iPad retail site:
Buy iPad Air at your favorite Apple Retail Store beginning at 8:00 a.m. on November 1. We’ll set it up just the way you like.* iPad mini with Retina display coming to stores later in November.
* Supplies may be limited and are available on a first-come, first-served basis.