The rules regarding carrying weapons on an airplane in the United States are simple: Unless you are a law enforcement official, you can´t. Regulations are more complicated for weapons in checked baggage, being a mixture of Transportation Security Administration (TSA) rules and individual airline policies.

No Weapons in Carry-On Luggage

Carry-on luggage has by far the most restrictive set of regulations for U.S. air travel; the only people allowed to carry weapons aboard U.S. airplanes are law enforcement officers. TSA regulations ban all weapons, as well as most tools and sporting items, from carry-on luggage. Even toy and replica firearms are specifically banned. Indeed, just trying to get on a plane with a carry-on weapon of any kind will likely result in your being detained and questioned during the security screening at the airport.

Checking Weapons

Firearms of all types, including handguns, may be stowed as checked baggage under certain conditions. TSA requires that a weapon be packed unloaded and in a hard-sided container that is properly locked. You must declare upon check-in that your luggage contains firearms, and you may also be required to fill out a Firearm Unloaded Declaration form at the counter.

Stowing Ammunition

TSA bans from checked baggage the black powder and percussion caps that are commonly used with antique firearms, as well as explosives, flares and fireworks. Past that, whether ammunition is permitted and how it is to be stowed as checked baggage is up to the individual airline. While all six of the major U.S. airlines permit ammunition, their specific requirements vary; check with the airline prior to packing for your flight.

Other Restrictions

Most other items that can be used as weapons, such as swords, clubs and spear guns, are permitted as checked baggage. Typically, they can be stowed just as any other form of luggage might be--although fishing spears, archery gear and similar equipment may require special packing, according to a specific airline's regulations. Other items based on chemicals are more complicated. TSA regulations permit pepper and mace sprays to be stored as checked baggage with some restrictions, but not flammable substances or materials containing poisons such as chlorine, and things like spray paint. So, anything involving fire is banned, and a good rule to follow is that any other item involving chemicals that is not specifically allowed is also banned.

Locks

Locks are required on checked baggage for all firearms. TSA recommends that you use one of its approved locks, which can be opened with a master key carried by TSA security personnel. If you use a lock that cannot be opened by a master key, inspectors will cut off and destroy it if you are not present to provide the key. In the case of firearms, if TSA cannot open the container for an inspection, you will be summoned to open it. As this will pose a serious inconvenience, if you are traveling with firearms you should absolutely either use a TSA-approved lock or simply give the lock's combination or key to TSA security personnel after declaring the firearm.