Darn good question that and one I was asked today by an overseas customer. The answer is really simple too. Avoid potted plants wherever possible. Why?
Some of them just don't travel well. Sure they can do 4-5 days in a box no problem but some plants take MUCH longer to arrive to overseas destinations. Take Greece for example - sometimes it takes 3 weeks for parcels to arrive there! Crazy heh...
So the plants that I recommend for overseas shipping are Tropica 1-2-Grow! Not only are the light in weight so they're cheaper to send, but they also survive for much longer periods in a box. And yes, they were fine for 3 weeks in a box (it was nice and cool though).
Not only that but because of the vitro jelly, it also means they have nutrients to keep them going when traveling (unlike potted plants). See the range of Tropica 1-2-Grow! plants by clicking here.