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.
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.
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.
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.
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.
