Flight crews, which report confrontations with unruly airline passengers more than 100 times a year, are warning that allowing pocketknives back on planes can make tense situations in the air even more dangerous.
"My concern is that it would essentially add fuel to the fire," says flight attendant Ian Funderburg, who's based in Charlotte. "My main concern is with safety. It's not so much that we're in fear, but it's an unnecessary risk that doesn't need to happen."
Travelers can start carrying small knives and sports equipment, such as golf clubs and hockey sticks, aboard passenger planes starting April 25, the Transportation Security Administration said last week.
TSA Administrator John Pistole justified loosening the restrictions, which have been in place since right after the Sept. 11, 2001, terrorist hijackings, as part of a shift to more risk-based security.
After hardening cockpit doors to protect pilots, the agency says its goal is to look for terrorists and explosives. "The focus is on what could present catastrophic damage to the aircraft," says David Castelveter, a TSA spokesman.
But some pilots, flight attendants and air marshals oppose the change, which has sparked a debate about dealing with unruly passengers - and whether allowing travelers to have items that can be used as weapons turns often stress-filled passenger cabins into a more dangerous place for other passengers and crew.
Incidents of so-called air rage do break out in the skies every few days or so.
Crew members filed 101 complaints last year about unruly passengers, who face fines up to $25,000, with the Federal Aviation Administration. The numbers were higher in previous years, with 140 in 2011, 149 the year before that and 176 in 2009.
But flight attendants say they don't report all incidents. Airlines worldwide collect internal reports of so-called air rage that they don't release, but which the airline trade group International Air Transport Association says rose 29% from 2009 to 2010, after rising 27% a year earlier.
Andrew Thomas, an associate professor at the University of Akron who's written books about air rage and aviation security, says stress has been ratcheted up aboard planes because of security hassles and more crowded planes. He says allowing small knives into the cabin will make flights less safe.
"Acts of aberrant, abusive and abnormal behavior known as air rage remain the most persistent threat to aviation security," Thomas says.
Crew members agree and worry that confrontations could become more incendiary with weapons.
Funderburg, the flight attendant, says a colleague on a recent flight confronted a man who wouldn't turn off his cellphone and became belligerent, finally lunging at the woman. "What if you added a knife to that situation?" Funderburg asks.
Disputes also can distract air marshals, who fly armed and undercover on some flights to discourage terrorist hijackings.
"There is no justifiable reason for implementing this policy, and it only serves to place law enforcement officers and flying Americans at greater risk," says Jon Adler, president of the Federal Law Enforcement Officers Association, which includes air marshals.
In line with global standards
Although the International Air Transport Association says air rage incidents remain "a serious concern," it supports the TSA's decision to loosen restrictions to match international standards.
Jean Medina, a spokeswoman for the trade group Airlines for America, says domestic airlines also support TSA's approach of combining its vast experience from screening billions of passengers with risk-based assessments to find security threats.
The move puts U.S. carry-on rules more in line with airline security standards set by the International Civil Aviation Organization, a branch of the United Nations.
Perry Flint, an association spokesman, says global standards give passengers confidence that they won't be subject to different security restrictions in different countries, which translates into fewer hassles.
"We believe that global standards, consistently applied, are a key element of effective security, as they have shown to be with safety," Flint says.
And a former TSA official says the agency created in the aftermath of 9/11 was never intended to stop every squabble on a plane.
"What we were trying to do is focus its attention on the next threat, instead of fighting the last war," says Jeff Sural, a former assistant administrator for legislative affairs at TSA now practicing law at Alston & Bird LLP. "We took care of that with a few things: locked cockpit doors, armed pilots, air marshals. What other threats are out there?"
The policy change leaves crew members worried about weakening a layer of protection in the security blanket for flights.
Mike Karn, president of the Coalition of Airline Pilots Associations, which represents 22,000 pilots, says the group rejects having knives of any kind in the cabin because they would put crew members and passengers in harm's way unnecessarily.
"We are concerned that the proposed changes to the prohibited items list could represent a step backwards in aviation security," Karn says.
Flight attendants are working to change the policy. Funderburg has begun a petition at change.org/TSAknives to keep knives out of aircraft cabins.
The Flight Attendants Union Coalition, which represents 90,000 flight attendants, also has a petition on the White House website in a bid to overturn the TSA decision.
Veda Shook, president of on of the coalition unions, the Association of Flight Attendants-CWA, is circulating a letter in Congress opposing the policy and plans to meet this week with House lawmakers who oversee TSA.
"We are totally appreciative of the cockpit door being reinforced. But what about the rest of us?" Shook asks. "It's a grave concern. If a weapon is introduced, that rapidly escalates the threat."