CraftStylish had a recent post on airline travel for knitters.  Below is the text from the TSA web site.

TSA info:  Transporting Knitting Needles & Needlepoint

Knitting needles are permitted in your carry-on baggage or checked baggage. However, there is a possibility that the needles can be perceived as a possible weapon by one of our Security Officers. Our Security Officers have the authority to determine if an item could be used as a weapon and may not allow said item to pass through security. We recommend the following when bring knitting needles on an airplane:

* Circular knitting needles are recommended to be less than 31 inches in total length
* We recommend that the needles be made of bamboo or plastic (Not Metal)
* Scissors must have blunt points
* In case a Security Officer does not allow your knitting tools through security it is recommended that you carry a self addressed envelope so that you can mail your tools back to yourself as opposed to surrendering them at the security check point.

Most of the items needed to pursue a Needlepoint project are permitted in your carry-on baggage or checked baggage with the exception of circular thread cutters or any cutter with a blade contained inside. These items cannot be taken through a security checkpoint. They must go in your checked baggage.