There are items that are prohibited from being on
the plane at all and then there are items that can be in your checked baggage
but not in your carry-on.
Go to your airline's website for the most up-to-date list of prohibited
items. If in doubt about an item, leave it home. There could be criminal
penalties attached to bringing a prohibited item to the
airport.
What can’t be brought into the cabin: Knives, box cutters, scissors
with sharp ends, swords, sporting goods (sticks/bats/arrows/cues), any type of
guns, tools (power tools, screwdrivers, hammers, saws, pliers, wrenches),
martial arts/self defense items (billy clubs, brass knuckles, mace spray, stun
guns).
Items that can’t be brought on the plane at all: Lighters, gun
powder, explosives (dynamite, fireworks, flares), fuels, gasoline, lighter
fluid, spray paint, fire extinguishers, bleach, oxygen tanks, poisons
(pesticides, insecticides, rodent poisons), bacterial cultures.
Luggage
When you are checking in a bag and want to lock it, use a TSA (Transportation
Security Administration) approved lock. They can be purchased almost anywhere,
even at the airport. You have the security of locking your belongings, yet
authorized airport personnel can make a hand search if they deem it necessary.