Knitting needles are usually made of wood, bamboo, plastic or metal. The TSA recommends that you travel only with softer bamboo or plastic needles and leave metal needles at home. Circular needles could in theory be used as a weapon, so the TSA suggests carrying circular needles less than 31 inches in total length. If you are choosing a new knitting project to take on a flight, or choosing between several projects to bring, it may be a good idea to choose ones requiring larger needles, which tend to have more rounded tips. Your carry-on luggage will be checked and x-rayed and individual officers have the right to prohibit knitting needles if they think they are too dangerous. You can minimize the risk of officers seeing your knitting needles as dangerous by avoiding thinner, more sharply pointed needles which appear more dangerous than fat, blunt ended ones.
In addition to knitting needles you may want to bring scissors and yarn needles for your project. The TSA states that scissors must have blunt points. To avoid any risk of having to leave your scissors at a checkpoint you could use a dental floss container, which contains a safe, small blade that could be used to cut yarn. If you need to bring a yarn needle, find a thicker plastic one if possible.
Because the security situation is always changing, there is always a risk that your knitting needles will not be permitted on a flight even if you follow the TSA's guidelines. You may happen to travel on a day when the threat level is elevated and TSA Officers have been instructed to be extra vigilant. There is always the chance that the particular official who scans your bags chooses not to allow your knitting needles on the flight. To be prepared for this chance, the TSA recommends that you bring a stamped self addressed envelope so that you can mail your knitting needles home. Without this you would have to surrender them at the airport. If you are prevented from taking your knitting needles on a flight, take the knitting project off the needles and either have a stitch holder to keep the work safe, or thread the live stitches onto a length of scrap yarn and tie it securely. There is no reason to abandon or mail your knitting with the needles.
