@MrIVI,
In one of author Barry Eisler's novels ("One Last Kill", I think), the protagonist, John Rain, makes a purchase of high-end Japanese rice paper [used for writing or origami, I can't remember]. He carefully swaps out the "cores" of these paper stacks with cash and carefully re-assembles the gift-wrapped package so that it is restored -- and appears to be nothing more than a beautiful souvenir gift from Japan as he travels from Narita Airport to Manila.
Another method that would make sense would be to look at charter flights where the security and inspections are less. This is the method that fake Korean SONY heiress and con-artist "Lisette" Lee aka Lisette Morita employed for her pot business before she was caught:
http://www.rollingstone.com/culture/news/the-gangster-princess-of-beverly-hills-20120831
