We use cardboard boxes, and we will stuff our empty panniers into the box to provide a bit of cushioning. Or occasionally, if we have a bit of foam or something, we'll put that around various parts of the bicycle. You can sometimes buy those colourful pool snakes or similar things and cut them up to use for padding, or bubble wrap.

On our current tour, we were able to purchase two cardboard bicycle boxes from Qantas (who does not charge anything for bicycles ), and we had some packing material - bubble wrap and some foam. We packed the bicycles in Melbourne and flew to Hong Kong. There we did not even open the boxes because we opted not to cycle in Hong Kong. Then we flew from Hong Kong to Taiwan (and then the charges for bicycles started). In Taiwan, we built the bicycles and were able to store the boxes at the hotel where we stayed on our first and last nights. Then we flew to Japan, built the bicycles, and stored the boxes at the hotel where we spent the first and last nights of our stay in Japan. Then we flew to London ... and there, sadly, we had to get rid of the boxes because we couldn't haul them all over Europe for 3 months.

We will have to see what we can find in Paris in a month's time. Evidently the airline we're flying with sells cardboard bicycle boxes. We'll have to see if that is still true when we get there. As for packing material, perhaps we can find some bubble wrap or something in a shop at the airport.