Schumer, D-N.Y., said Sunday the TSA's new policy puts passengers and crew members in danger. He said the items, which were banned after the Sept. 11 attacks, could be used as weapons.
"While it's true that pilots are safe, locked behind cockpit doors, these dangerous items still pose a significant hazard to the flight crew, other passengers, and even the integrity of the plane," said Schumer.
Schumer is the latest public figure to join a growing opposition to the proposed plan, which is set to be implemented April 25.
On Friday, the head of Delta Air Lines voiced his opposition to allowing small knives on planes in a letter to TSA Administrator John Pistole obtained by The Associated Press.
Aviation insurers as well as unions representing flight attendants, pilots and federal air marshals have also publically opposed the plan.
Items like box cutters and razor blades are still prohibited under the new policy. But passengers will be allowed to include in their carry-on luggage novelty-size baseball bats less than 24 inches long, toy plastic bats, billiard cues, ski poles, hockey sticks, lacrosse sticks and two golf clubs.
Knives permitted under the policy must be able to fold up and have blades that are 2.36 inches or less in length and are less than 1/2-inch wide.
TSA spokesman David Castelveter said last week that the policy change was based on a recommendation from an internal TSA working group, which decided the items represented no real danger. He added that gun-carrying pilots, federal air marshals and airline crew members trained in self-defense provided security to protect against the misuse of the newly added items.