The policy change announced Tuesday by TSA Administrator John Pistole changes U.S. security standards to international standards. In a statement, the agency said the change will allow it to concentrate on more serious safety threats, after it determined that the items presented no real danger.
The new policy allows folding knives with blades that are 2.36 inches or less in length and are less than 1/2-inch wide. The policy is aimed at allowing passengers to carry pen knives, corkscrews with small blades and other knives.
Passengers also will be allowed to bring onboard as part of their carry-on luggage novelty-sized baseball bats less than 24 inches long, toy plastic bats, billiard cues, ski poles, hockey sticks, lacrosse sticks and two golf clubs, the agency said.
"These are popular items we see regularly," said TSA spokesman David Castelveter in a statement. "They don't present a risk to transportation security."
Box cutters, razor blades and knives that don't fold or that have molded grip handles will still be prohibited, the TSA said.
The policy goes into effect on April 25.
"We're not pre-9/11, we're post 9/11. We know that these small, little items are unlikely to be used again to try and hijack an aircraft," said Jeff Price, a professor at Metro State University of Denver. "Frankly, with sequestration, we need to keep the screening lines moving."
The Flight Attendants Union Coalition is blasting the TSA's decision to allow knives on planes, calling it "dangerous" and "short sighted." It said the changes will make "the lives of TSA staff easier, but not make flights safer."
The Associated Press contributed to this report.