Leaving this item on a keychain on hand carry will probably get confiscated. Due to the fact it can start a fire. I have seen some TSA will allow it for military returning from overseas in uniform from a deployment.
I've flown on commercial flights a number of times with a butane lighter in my jacket pocket, and it's never been questioned or confiscated, even though the TSA has stolen nail clippers and tiny folding scissors with 1-inch blades from me. There's no rhyme or reason to what they do and the rules change frequently.
it will have to be checked because it is a product that can caause fire. It can be placed in you regular lugage. most of the time they do not look at the key rings and might not ask about it. But if you do take it on i would remove the blade first. Plus TSA will take it if they know it is a fire stater and you could get jail time too. So I would keep it in checked bags.