Summary rule of thumb:
US Domestic flights = $80/each way to take bike in box as luggage
International flights = no charge to take the bike as luggage
Bike boxes (cardboard) purchased from the airline; range $8 - $20 per box. Always check AirFrance first (usually the least expensive also). They always have boxes; check in advance with other airlines or you may be at the airport trying to get home and NO box! These boxes are fine for packing your bike; but, make sure components have some protection also by using bubble wrap if you have it.
http://www.dulcinea.crazyguyonabike.com
Bruce Northcutt