Pocket knives may be packed in checked luggage, but never in a carry-on bag.
The Transportation Security Administration (TSA) bans certain items for air travel due to their potential to cause harm, whether intentional or accidental. Some items may be packed in checked luggage (but not carry-on) while others are banned completely. When in doubt, it's advisable to either pack the item in question in checked bags or simply leave it at home to avoid problems.
Sharp Objects
Razor blades are allowed in checked and carry-on bags.
The TSA allows most sharp objects to be packed in checked luggage, provided they are properly sheathed for the protection of baggage handlers. Scissors are one exception; they may be packed in carry-on luggage as long as the blade length falls under four inches. Other sharp objects, including razor blades, box cutters, ice picks, meat cleavers and swords, are forbidden in carry-on items only. Disposable razor blades for shaving and extra cartridges are permitted in both checked and carry-on luggage.
Sporting Goods
It's better to leave unnecessary sporting goods, like baseball bats, at home.
All sporting goods are prohibited in carry-on items due to their potential to cause serious injury. Baseball bats, hockey sticks, cricket bats, bows and arrows, ski poles, and spear guns may not be brought into the airplane's cabin under any circumstances. Although some sporting goods may seem innocuous enough, it's better to err on the side of caution. If you don't absolutely need the item during your trip, leave it at home and rent a substitute at your destination. Never pack anything in carry-on bags that could reasonably be construed as a weapon.
Guns & Ammunition
Guns and ammunition are usually allowed in checked bags if fully disarmed.
Properly packed guns are allowed in checked luggage but never in carry-on luggage. Travelers wishing to pack ammunition, however, must check with their airline before packing it; some airlines do not allow ammunition at all, even in checked luggage. All guns -- including small personal firearms, flare guns, BB guns, and compressed-air (paintball) guns --- must always be completely disarmed and unloaded and packed in a locked container with hard sides. All guns, ammunition, gun accessories and even gun replicas must be declared to the airline at check-in.
Tools
Axes and other sharp tools must be sheathed to protect baggage handlers.
TSA allows all tools in checked bags if they are sheathed to prevent injury. Axes, hatchets, crowbars, hammers, cattle prods, drills and saws must be properly packed and checked. Screwdrivers, wrenches and pliers with a length shorter than or equal to 7 inches may be packed in carry-on baggage.
Chemicals
Spray paint and other aerosols are not permitted at all in any luggage.
The TSA has a long list of prohibited chemicals. Anything explosive or flammable is completely forbidden, including fireworks, chlorine, lighter fluid, any kind of gas, bleach, matches or aerosol. The TSA allows one book of matches in carry-on luggage, but matches in checked bags are absolutely forbidden. Small compressed gas cartridges (up to four - two vests and two spares) are allowed in checked and carry-on luggage.
Tags: carry-on luggage, checked luggage, allowed checked, checked bags, packed checked