Ironically, even though baseball bats, hockey sticks, golf clubs, etc. are expressly prohibited as carry-on items by the TSA, the rules are silent when it comes to tripods and monopods (even though my metal Bogen monopod with a swivel head attachment would be an even more effective weapon than an aluminum bat). However, there are first-hand reports of TSA agents turning away people when they have attempted to carry such items on. It's in the minority, but it happens. The agent will usually have the final say, and it's probably not worth trying to make a literal "federal" case out of the fact that your tri/monopod isn't listed as a prohibited item. So, the bottom line is: You will very much likely not have a problem from the TSA if you attempt to carry on your 'pod... but don't be shocked it you're one of the "lucky" ones that does have a problem.