WASHINGTON » Flight attendants, pilots, federal air marshals and even insurance companies are part of a growing backlash to the Transportation Security Administration’s new policy allowing passengers to carry small knives and sports equipment like souvenir baseball bats and golf clubs onto planes.

The Flight Attendants Union Coalition, which representing nearly 90,000 flight attendants, said it is coordinating a nationwide legislative and public education campaign to reverse the policy announced by TSA Administrator John Pistole this week. A petition posted by the flight attendants on the White House’s “We the People” website had more than 9,300 signatures early toiday urging the administration to tell the TSA to keep knives off planes.

“Our nation’s aviation system is the safest in the world thanks to multilayered security measures that include prohibition on many items that could pose a threat to the integrity of the aircraft cabin,” the coalition, which is made up of five unions, said in a statement. “The continued ban on dangerous objects is an integral layer in aviation security and must remain in place.”

Jon Adler, national president of the Federal Law Enforcement Officers Association, whose 26,000 members include federal air marshals, complained that he and other “stakeholders” weren’t consulted by TSA before the “countersafety policy” was announced. He said the association will ask Congress to block the policy change.

The Coalition of Airline Pilot Associations, which represents 22,000 pilots, said it opposes allowing knives of any kind in airliner cabins.

“We believe the (terrorism) threat is still real and the removal of any layer of security will put crewmembers and the flying public unnecessarily in harm’s way,” Mike Karn, the coalition’s president, said.

The new policy, which goes into effect on April 25, permits 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 small knives.

Passengers also will be allowed to include in 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. Items like box cutters and razor blades are still prohibited.

There has been a gradual easing of some of the security measures applied to airline passengers after the Sept. 11, 2001, terrorist attacks. The new policy conforms U.S. security standards to international standards and allows the TSA to concentrate its energies on more serious safety threats, the agency said when it announced the change this week.

The policy change was based on a recommendation from an internal TSA working group, which decided the items represented no real danger, the agency said.

A TSA spokesman said the presence on flights of gun-carrying pilots traveling as passengers, federal air marshals and airline crew members trained in self-defense provide additional layers of security to protect against misuse of the newly allowed items.

Not all flights, however, have federal air marshals or armed pilots onboard.

The new policy has touched off a debate over the mission of TSA and whether the agency is supposed to concentrate exclusively on preventing terrorists from hijacking or blowing up planes, or whether it should also help protect air travelers and flight crews from unruly and sometimes dangerous passengers.

“The charter, the mission of TSA is to stop an airplane from being used as a weapon and to stop catastrophic damage to that aircraft,” David Castelveter, a spokesman for the agency, said. Pistole’s position is “these small knives, these baseball bats, these sporting items aren’t going to contribute to bringing an airplane down,” he said.

In era of reinforced cockpit doors and passengers who have shown a willingness to intervene, the threat from terrorism has been greatly reduced, Andrew R. Thomas, a University of Akron business professor and author of several books on the airline industry and security, said.

Rather, “acts of aberrant, abusive and abnormal passenger behavior known as air rage remain the most persistent threat to aviation security,” he said.

The International Air Transport Association recently reported that the incidence of air rage cases was way up, with an estimated 10,000-plus such events annually, Thomas said.

Adler, representing the air marshals, said aviation security is neither “terrorist proof nor psycho proof,” and both should be protected against.

TSA’s “primary concern, and their only concern, is to protect the cockpit to make sure the planes aren’t turned into missiles,” he complained. “Traveling Americans are expendable, disposable and otherwise irrelevant to air travel safety.”

The new policy has aviation insurers concerned as well.

“We think this move is a bad idea, and isn’t in the interests of the traveling public or flight crews in the aviation industry,” said Joe Strickland, head of American operations for Allianz Global Corporate & Specialty, a leading global aviation insurer.

“Safety is the highest priority of every commercial air carrier, flight crew member and air traffic controller,” he said. “We don’t see how these changes support this priority.”