
TSA Administrator John Pistole, speaking at a conference in New York on March 5, 2013, announced a major policy change for carry-on items beginning April 25, 2013. While it doesn't name tripods themselves, it clearly implies a change in attitude toward them being taken into airplane cabins in the US.
The details of the policy change were detailed in a
statement on TSA's website. In the statement on Changes to the Prohibited Items List it says,
“Through TSA’s layered approach to security, and to align more closely with International Civil Aviation Organization standards, effective April 25, 2013 TSA will allow knives that do not lock, and have blades that are 2.36 inches or 6 centimeters or less in length and are less than 1/2 inch in width, novelty-sized and toy bats, billiard cues, ski poles, hockey sticks, lacrosse sticks and two golf clubs as part of their carry-on baggage. This is part of an overall Risk-Based Security approach, which allows Transportation Security Officers to better focus their efforts on finding higher threat items such as explosives.”