Originally Posted by
StanSimmons
http://deviating.net/firearms/packing/
There is a lot of good information at the above site. On the US side, you aren't REQUIRED by FAR 1544.293 to fill out the paperwork for an airsoft, but if you do it will keep the TSA from freaking out when they spot the airsoft.
If it's in a locked hard-sided case as a declared "firearm," it might even still be there on arrival.
Otherwise, it may be chosen by a lucky TSA employee as a gift for themselves or a relative.