JACKSONVILLE, Fla. -

Two days after the Transportation Security Administration announced it will allow some pocket knives on airplanes, those who work on planes are fighting back.

Knives were banned in the wake of the Sept. 11 attacks. Now with new rules set to take effect next month, Flight Attendant Unions is pushing for them to be reversed, saying the new regulations will endanger the lives of those working and traveling on planes.

Many people are having a hard time trying to understand why they will soon be allowed to take a knife on a plane, but not a tube of toothpaste or a bottle of shampoo. They say it's not just about convenience, but about safety.

When Kimberly Hall and her daughter fly to Ohio for Christmas this year, they'll board their planes knowing anyone on board could be carrying a pocket knife.

"That is the most ridiculous thing I've ever heard in my life," Hall said. "Got to take my shoes off and my belt before I go through security, but you can take a pocket knife."

Pocket knifes will be aloud on board if the blade is 2.36 inches or shorter and less than half an inch at its widest point. They can't lock or have a molded grip.

The TSA says it's all in an effort to align more with international standards and focus efforts on finding higher-threat items like explosives.

Mike Rehfus says he's comfortable with the change.

"I don't have a problem with it," he said. "Most people carry pocket knives for other things, other things than to use illegally in other manners like that."

But not everyone agrees, especially those who make their living working in planes. Kelly Skyles, of the American Airlines Flight Attendants Union, says the organization plans to ask TSA to reverse its decision.

"It was box cutters and small knives that were used by the terrorists on 9/11 that killed my colleagues," Skyles said.

Although box cutters are still prohibited, some say the blades are comparable to some pocket knives that will be allowed.

Skyles argues any knives on a plane pose a safety risk.

"We're very disappointed of the decision, as well as being left off the table and not being part of the decision process," Skyles said.

Several other groups, including the Federal Law Enforcement Officers Association and Association of Flight attendants, are speaking out against the new rules.

Aviation attorney Ed Booth believes the groups have a powerful voice, as will passengers, and that could lead to the TSA reversing its decision.

"I predict that's what's going to happen," he said. "Once they think this through to the worst-case scenarios that they're going to have to rescind this."

Aside from pocket knifes, baseball bats, hockey and golf clubs will also be allowed on board next month.