(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."
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.
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.
"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.