This is a good question with a lengthy answer. There is a long list of things that shouldn't be carried on a plane. Most items that are banned have to do with anything that could be used as a weapon. Your probably thinking, Jet Li can make a weapon out of anything. In the movies this is true but in real life certain items tend to be more dangerous than a paper clip. Below is a list of things that can't be carried on an airplane, some maybe obvious and some may surprise you.
You cannot bring a knife on an airplane unless it is plastic or a rounded butter knife. This is obvious, someone can do some serious harm with a knife therefore there are only the two exceptions.
Shampoos, conditioners, toothpaste, toiletries etc. must be 3 oz. or smaller. They will not let you board an airplane with a full-size bottle of shampoo. Additionally, be sure to put all your toiletries in a large plastic baggy and take it out of your carry on bag when going through the x-ray.
Some scissors are acceptable but they must be plastic or metal with round or blunt ends or they must be shorter than 4 inches long.
You cannot bring a box cutter of any kind on an airplane.
You cannot bring an ice pick or ice ax (whatever that is) on an airplane.
For all you traveling butchers, you cannot board an airplane with a Meat Cleaver.
According to the Transportation Security Administration you cannot bring a Saver or Sword on an airplane.
You cannot carry on a Baseball Bat, Bow and Arrow, Cricket Bat, Golf Club, Hockey Stick, Lacrosse Stick, Pool Cue, Ski Pole or Spear Gun.
You may not bring a BB Gun, Air Gun, Flare Gun, Firearm, Gun Lighter, Gun Powder, Percussion Cap, Pellet Gun, Starter Pistol, Ammunition or any Gun that resembles or replcates a Firearm.
You cannot carry on an Axe, Hatchet, Cattle Prod (this is why my father-in-law doesn't fly), Crowbar, Hammer, Drill with bits, Saw, or any Tool greater than 7 inches in length.
For all you MMA fans, you cannot carry on a Billy Club, Black Jacks, Brass Knuckles, Kubatons, Mace or Pepper Spray, Night Stick, Nunchakus, Stun Gun, Throwing Star or pretty much any Martial Arts Weapons.
Explosives cannot be carried on an airplane says Captain Obvious. For all the pyros out there, that means no Blasting Caps, Dynamite, Fireworks, Flares, Hand Grenades, Plastic Explosives or any replicas.
Aerosols are limited to toiletries.
Fuels cannot be carried on a plane. You cannot bring Gasoline, Gast Torches or Lighter Fluid on a Plane.
You can bring a lighter on a plane but it cannot have any lighter fluid in it.
Don't bring your Torch Lighter, Strike anywhere Matches (you can bring one book of safety matches only). '
You cannot bring any Flammable Paints, Turpentine, or Paint Thinner on an airplane.
You cannot bring Chlorine, Fire Extinguisher, Liquid Bleach, Spillable Batteries, Spray Paint or Tear Gas on a plane.
You cannot bring a Beverage brought from home or purchased prior to reaching the security check point unless it is in a container smaller than 3 oz.
You cannot bring full size canned or jarred food. It must be in a container 3 oz. or smaller.
If your bringing a Gel based sports supplement it must be 3 oz. or smaller. The same is true for Jell-O, Pudding, Whipped Cream and Yogurts.
You cannot bring any Gel-type Candles, Gel Shoe Inserts, Flammable Liquid, Gel or Aerosol Paint on an airplane.
FInally, don't take your Snow Globes on a flight.
So what did we learn? If you have any type of fluid be sure to put it in a container that is 3 oz. or less. Put the container in plastic bag and take it out of your carry on when you go through security.
If you are not sure about a particular item then don't bring it. If it's absolutely necessary contact your Airline. Be sure to present anything and everything that is questionable. It will save you lots of time. Fly safe and don't complain, these rules are in place to save lives not to be a hassle.