The U.S. Transportation Security Administration will let people carry small pocketknives onto passenger planes for the first time since the Sept. 11 terrorist attacks, along with golf clubs, hockey sticks and plastic Wiffle Ball-style bats. The agency will permit knives with retractable blades shorter than 6 centimeters (2.36 inches) and narrower than 1/2 inch, TSA Administrator John Pistole said…