The quick answer is yes, but it also depends on the country and the level of heightened security risk it is currently facing. Some countries, including Cuba, will forbid them from going through the security checkpoint. In Canada and the United States, I've never had an issue.

You are best to check the following two websites for current, up-to-date information on the level of security.
- TSA Website - United States.
- CATSA Website - Canada.
The security checkpoint ultimately has the final say. Yes, many of us have been through a security checkpoint where the agent is on their last nerve. Sometimes, to put it politely, the rules are inconsistent.
Thing to Watch For
Be careful with those scissors. They must be under 4" long from the tip of the blade to the back of the handle. I recommend getting a dedicated pair of nail clippers and using that instead.
If you don't need drama, leave the scissors at home and substitute with nail clippers.
Horror Stories
Yes, people have hooks, knitting needles, and yarn taken from them. These could be true, but they could also be rumour mill crap from the internet that has no factual basis. I say very little to the agents unless necessary.
Final Recommendations
- Have a partial project already started and in your carry-on.
- Remove the ball bands from the yarn, as they could accuse you of selling yarn if travelling across an international border.
When I talked to an airline steward, they said they would rather see me crochet or knit than drive them crazy. Our entertainment is portable, and on the last couple of flights I have had, the entertainment system has been non-existent and/or broken. I'm fine as long as I have my yarn.
Generally speaking, the stewards have inquired about what I am making and start a nice, creative conversation too.
Have a good flight and knit on.

Have you completed this project. Show me!