( CNN ) -- Echoing an airline chief and flight attendants , U.S. Rep. Ed Markey came out Saturday against the Transportation Security Administration 's move to allow small pocketknives on airplanes , calling it unnecessary , counterproductive and potentially dangerous . In a letter to TSA Administrator John Pistole , the Massachusetts Democrat expressed concern about the new policy and asked it be reversed . `` The attacks on September 11 , 2001 , demonstrated that in the confined environment of an airplane , even a small blade in the hands of a terrorist can lead to disaster , '' wrote Markey , who is running for the U.S. Senate seat recently vacated by John Kerry . `` ... In addition , the additional responsibility of assessing which knives meet the new requirements could be a distraction for already overburdened screeners at TSA checkpoints , potentially leading to increased wait times and decreased security . '' Knives on a plane ? Really ? Under the new rules outlined this week , knives with blades no longer than 2.36 inches ( 6 centimeters ) and less than a half-inch wide will be allowed in airline cabins as long as the blade is retractable and does not lock into place . Razorblades and box cutters are still prohibited . The rules also allow passengers to carry two golf clubs , toy bats or other sports sticks -- such as ski poles , hockey sticks , lacrosse sticks and pool cues -- aboard in carry-on luggage . Pistole said the move brings the United States into alignment with international rules and are keeping with his `` risk-based security '' approach . Kip Hawley , who oversaw the TSA from 2005 to 2009 , said the search for knives interferes with the search for objects such as bombs and toxins that can threaten aircraft . Ex-TSA chief backs decision . But others have sharply criticized the change , which takes effect April 25 . They include the Flight Attendants Union Coalition , a nearly 90,000-member group that has launched a campaign to reverse the TSA 's decision . The policy is also opposed by the Federal Law Enforcement Officers Association , a union representing more than 26,000 officers from 65 agencies . And Delta Air Lines CEO Richard Anderson said Friday that he shares the same `` legitimate concerns '' as his flight attendants . Delta CEO opposed to allowing small knives on aircraft . `` If the purpose is to increase security checkpoint flow , there are much more effective steps we can take together to streamline the security checkpoints with risk-based screening mechanisms , '' he wrote in a letter to Pistole .
The TSA said it would allow small knives onto planes , starting April 25 . The agency 's chief says this brings the U.S. in compliance with world norms . U.S. Rep. Ed Markey calls the move unnecessary and potentially dangerous . Delta 's CEO , unions for flight attendants and federal law enforcement also oppose it .