Simply put... yes... maybe!
Ok, ok, you can stop rolling your eyes now. But seriously, the answer can be a confusing one to decipher so I'm going to share my experiences and a list of resources to help you prepare for your upcoming travel plans so that you aren't at risk of losing your needles... much less your precious WIP (work in progress) as you go through security.
Yes they are!
The current TSA (Transportation Security Administration) has a pretty clear policy on US flights (flights that take off and land within the US): yes, yes, yes! You are not only allowed to pack them in your checked bags, but you can take them right onto the plane with you and knit to your hearts content! But! Consider getting yourself a set of point protectors since the TSA does specifically add:
Any sharp objects in checked bags should be sheathed or securely wrapped to prevent injury to baggage handlers and inspectors.
I have to assume the same applies to carry-on bags since they do often run their hands through the odd purse or backpack. It's definitely not worth an upset TSA agent!
CATSA (Canadian Transportation Security Administration), our brothers and sisters to the north, have the same policy on knitting needles and crochet hooks and even take the description one step further to include the following details:
Knitting needles and crochet hooks of any size and made from any type of material (e.g. plastic, aluminum, bamboo) are permitted in carry-on or checked baggage.
What you'll need to be aware of is the rules governing the airport you are departing from, not landing at, and even which airline you are flying with. Take, for example, my most recent trip to Scotland (not that recent... it was 3 years ago now, sigh...) where I was able to take my knitting needles through security in my carry-on bag when leaving the US, but, when departing Scotland, despite flying with an American airline, I was told that the security agents would most definitely confiscate my knitting needles. Why, you ask? Because the tip was metal. Just a 1" metal tip on my otherwise non-metal needle caused the issue. I was assured that had the needle been wood, I'd have had no issue.
The European Union isn't quite as cut and dry when it comes to permissible crafting items. They specifically discuss scissors (no more than 6 cm / 2.3" measured from the fulcrum) which many of us are familiar with, but there's a bit of a grey area surrounding "tools".
On their list of prohibited items is the following:
...tools with a blade or a shaft of more than 6 cm capable of use as a weapon, such as screwdrivers and chisels
As knitters and crochet'ers, we know the woes of sitting down on a rogue needle/hook and know they can definitely cause some damage but the items referenced in this article are metal. So, based both on the list of items being metal AND on the experience I had in Scotland, consider taking non-metal needles. We carry both circular, straight and DPN needles in bamboo that should be travel-safe.
Better safe than sorry!
While most online forums and websites listing permitted and non-permitted items suggest that knitting needles are generally not a problem, the trend towards knitting needles getting on airplanes leaving Mexico is a no-go! Aeromexico is taking a hard-line on sharp objects of any kind:
Axes, knives, pocket knives, letter openers, swords, scissors, box cutters, scalpels, needles, and items with pointed tips and blades
I've read more than one account of knitters losing their needles while departing Mexico (but not flying in so you can knit at least one way) so be sure you've stowed your beloved WIPs in your checked baggage to avoid disappointment!
Just in case!
Travel rules and permissible items change all the time - so while this list is accurate today, new publications can go live tomorrow. Always be sure to check the rules of the country and airline you're flying with before you fly.
But here's a handy tip: consider taking a padded mailing envelope and sheet of stamps with you when you travel so that, on the odd chance you get stuck in a WIP-losing situation, you can mail your package home to yourself!