Standard 14 day return policy: http://store.apple.com/us/help/returns_refund
You can return your purchase no questions asked within 14 days and turn around and buy the newer model if you prefer.
If you are not in the US; go to the policy site of your home country and it should be in there.
Cool, thanks. I just got a new Air about 2-3 weeks ago, but after seeing the most recent news story showing the only improvement is a slightly updated processor I think I'm fine with my 2013 Air.