I traveled with my wife to France recently with my Bike Friday folders. I boxed them up in the US with boxes of no more than 62 linear inches. ( airline requirements) The boxes took a while to design. I used rolled up cardboard tubes to prevent the bikes from getting crushed and heavy duty parachute cord and duck tape to secure everything. The cord gives you a handle. This concept works great, you can reuse them, they are lighter than a suitcase so you can ship more stuff inside the boxes, you can ditch the boxes like we did when you arrive, you dont have to tow the suitcase around on your bikes, its easy to find cardboard to build return flight boxes. They are not too easy to carry and are susceptible to rain, our boxes survived a terrible storm in New Jersey and then in France, we couldn't have used them again. Maybe wax them? Good luck.