That has more to do with HOW it is shipped. Depending on the strength of the magnet, it may not be legal for it to be air shipped or carried on a passenger-carrying aircraft. There are very strict international rules on magnets, chemicals, and other hazardous materials.
Strong magnets can affect equipment in an airplane.
Banned items
The following items are completely banned from aircraft, and should not be brought to the airport:
Explosive and incendiary materials
Flammable items
Gasses and pressure containers
Matches
Oxidizers and organic peroxides
Poisons
Infectious materials
Corrosives
Organics
Radioactive materials
Magnetic materials
Marijuana (cannabis)
In order for magnets to be shipped by air:
For air shipment purposes, magnets are considered "dangerous goods". As such, the International Air Transport Association's (IATA) Dangerous Goods Regulations (DGR) must be followed.
Flux measurements of all packages containing magnets must measure less than 0.00525 gauss 15’ from the package. If flux measurements are less than 0.002 gauss when measured 7’ from the package, the package is not considered to contain magnetic material, and hence is not classified as Dangerous Goods. However, unless the package is extremely secure and there is no chance that the contents will shift or that shielding will be damaged in transit, it is safer to proceed as though the package falls under the DGR.
Packages containing magnetic materials must be clearly identified according to Packing Instructions 902. This calls for a "Magnetized Material" label to be affixed, and for a Shipper's Declaration of Dangerous Goods to be provided to the carrier.
Personnel responsible for shipping magnets by air are required by the Federal Aviation Authority (FAA) to be trained for that purpose and for those training records to be maintained. Contact your carrier for more information and guidelines.
Magnets in any case are forbidden by the IATA from being in carry-on luggage.
