The TSA has lifted the ban on knives of a certain size. Allowed in carry-on are knives if the blade is no longer than 2.36 inches or 6 centimeters in length, the blade width is no more than ½ inch at its widest point, doesn't have a locking or fixed blade and doesn't have a molded grip. (TSA)
A knife is prohibited if the blade is longer than 2.36 inches or 6 centimeters in length, the blade width is more than ½ inch at its widest point, has a fixed blade or locks firmly when in use and has a molded grip. (TSA)
Small bats are now allowed on the aircraft but only if they're a certain size. Bats that are more than 24 inches and more than 24 ounces cannot be put in carry-on, but anything less than than can brought on board. (TSA)
The TSA will allow carry-on sports equipment such as billiard cues, ski poles, hockey sticks, lacrosse sticks and no more than two golf clubs. (TSA)
Razor blades and box cutters are still not allowed. (TSA)