Air guns, guns that fire BBs or pellets using the force of compressed gas aren't regulated by federal agencies like traditional firearms are. Because of this, the laws in regard to air guns vary widely from state to state, although the overwhelming majority of states only loosely regulate air gun use and possession.
The Bureau of Alcohol, Tobacco and Firearms regulates the sale and trade of firearms, though it defines a firearm as a weapon that uses the explosive force from the detonation of gunpowder as the means to propel a projectile. Air guns don't use gunpowder to fire pellets and BBs, so they're outside the scope of federal regulation. Because of this definition, most states are left to enforce air gun laws as they see fit.
Air Travel and Air Guns
The Transportation Security Administration bans the carry-on possession of air guns on all flights. This ban applies not only to BB and pellet guns, but also to paintball and AirSoft weapons. Travelers are permitted to travel with air guns, as long as they're in checked luggage and inaccessible during flight.
Postage and Air Guns
The United States Postal Service bans mailing compressed gas canisters unless they are empty, so air guns that use cartridges as propulsion may not be mailed. BB and pellet guns that fire with a pump action and do not contain compressed gas may be mailed.
Many states regulate the possession and use of air guns. While regulations vary from state to state, common restrictions include age restrictions that bar anyone under the age of 16 to 21 from purchasing air guns. Other restrictions may prohibit the use of guns on public property, the possession of guns on public property and the transport of guns that aren't inside a case or an otherwise inaccessible location.
In states where air guns are largely unregulated, many large cities restrict the use of air guns within the city. Cities such as New York, Chicago and Philadelphia all restrict the unregulated possession and use of air guns anywhere inside city limits other than at an approved firing range or other facility. In these municipalities, air guns may need to be transported in a locked case.