I have done both, and now I prefer to carry it on out of paranoia. The first time I flew with a tripod, i put it into my checked bag, and upon opening the luggage at my destination there was inevitably a note from the TSA saying they had opened my luggage for inspection. After that, I strapped the tripod to my camera bag, and this being the first time I had done this my camera bag was my only carry-on item. I figured if they made me separate the items that I would still be within the allowed two carry-on items rule, but the TSA didn't seem to care and so that's how I travel with a tripod now.