Ask anyone for plumeria cuttings, most people are happy to share. Then take them to your place, wash them well and find a box to fit them in. Take this open box to the USDA station at the airport before you leave, they will inspect the cuttings and seal the box for you and you can then either take it on the plane or mail it to yourself.
This is not a lengthy or complicated procedure and protects the agriculture from unwanted pests that might otherwise be transferred.
