I grappled with this problem on a recent trip to the UK. My solution was to buy a simple bike bag called the Tardis from Groundeffect, cost about $90

http://www.groundeffect.co.nz/produc...il-TAR-BAG.htm

You have to take the wheels, pedals etc off the bike, but it only takes 30 mins to do this. The bag is unpadded, but I used my gear to pad the sides of the bag and it worked really well. The great thing about the Tardis is that you can fit it in a taxi which makes it far easier to get to the airport than a cardboard bike box. Once at your destination the Tardis folds down to the size of a phone book and weighs about 2lbs so you can carry it, although it's easier just to post it to your final destination. Here's a bit about flying with the Tardis, I didn't use cardboard padding on the return trip and it worked fine.

http://www.crazyguyonabike.com/doc/p..._id=97931&v=Ck