Delay with MBA 13 shipping

I ordered MBA 13 (256Gb/2.13GHz/4Gb)on 11/23 from Apple website. It was supposed to arrive a week later - 11/30. However, Apple website still shows that it has not been shipped yet. In response to my email to Apple I received:

===================
Dear Apple Education Customer,

Due to an unexpected delay, we are unable to ship the following item(s)
by the date that you were originally quoted:

MBAIR 13.3 CTO
will now ship on or before
Dec 09, 2010

Please note that product availability can change rapidly, and it is
possible that your order may ship much sooner than we anticipate. You
may even receive a shipment confirmation between the time we send this
email and the time that you read it.
=============

Is this something normal or not? Possible parts shortage for MBA 13?