I just flew back from Tokyo and packed a 3rensho frame in a cardboard box. Wrapped the frame in Tshirts and reinforced the box with folded up corogated cardboard. A big risk, I know. But it arrived fine and didn't seem to have been opened. Narita had an oversize baggage department and a big xray machine that I watched the box go through. BTW, I flew United and they didn't charge me anything extra.