Can you ship air pistols via the USPS?

No. An air pistol (or CO2 pistol) that has enough energy to be usable as a weapon may only be mailed by a person holding a Federal Firearms License as a dealer or manufacturer of firearms. While Federal Law in the US does no treat an air pistol as a firearm, the USPS Domestic mail manual classes them as a pistol, and restricts mailing. Link to the USPS regulation:http://pe.usps.com/text/dmm300/601.htm?PE_DMM300_HTML_5&dtype=2#wp1065404