Another option would be to buy a bag (69€) from
Decathlon:
http://www.decathlon.fr/housse-de-transport-1-velo-id_8023151.html
I think they do click and collect so you can order online and collect from the store.
Or you could just do a circular tour, and leave the bag/box at a hotel near your arrival/departure point. I've never quite understood whys many people have their hearts set on doing an A-B tour when a circular tour would make the logistics a lot simpler.[/QUOTE
I have flown into Pisa and out of Venice. Otherwise I would have had to either ride or train back to Pisa. Using the bike bag I posted on here it is not a problem. I roll it up and stick it with my gear and off I go from the airport. I must have used that type of bag about 20 times and have had no damage. I must be lucky.