You will get a lot of people saying that they've had no problems and then some saying that they've had their needles taken away. Which means you're taking your chances. I would take a very cheap pair of needles with you so that if they take them, you won't be upset to lose them. And you really may get them taken, and if you argue about it, you're going to be seen as a threat, so be prepared to give them up and never get them back. (They haven't figured out that yarn can be used to strangle someone, yet, so they won't take your yarn away.) The TSA site will say that it's okay, but they make the disclaimer that it's up to the checker. To minimize the chances of them thinking they could be dangerous, I would take a project that uses thin needles rather than thick, and never metal, never circular. Swallow Casein is a good choice, cheap bamboo, Daisy, and there is a kind of knitting needle which is very flexible, you can bend them in 2 and they were in bright colors. Someone at my LYS had them, and I looked them up on line a couple of years ago, but I've never seen them since and can't find them now.