I agree with Gerald, you want to carry it on.
Unfortunatly, due to my location, I will have to 'check it' in. Then there's Customs, and all the other things I have to contend with.
I start with a small layer of light, soft foam 1/2" thick. Then a piece of styrofaom (white kind works fine) with cut outs for anything "dangling." All flat portions should be resting on the styrofoam. Place styrofoam pieces all around so there is no side-side movement. Then build up the strofoam on top of the plane (wings etc) with pieces leaving spaces for anything sticking-up. A piece of soft foam on top and close the box to compress the foam on top and bottom a bit. That holds everything in place. I have shipped a model to myself once (saved a BIG headache) and had no damage.
Postal mailing boxes found at the post office are a good find for the size of most 48th planes. And cheep too. Most will fit into the compartments on commercial filghts.