Hi
ive had bike bag's before, but i find they are to heavy to use on planes. Instead i went for a big hockey bag (it has wheels so you wont have to carry the bike(most sports shops has them))...Bike fits nicely(wheels, pedals and stem is taken off) and total weight is under 20kg, so it can be check in as a regular bag. inside the bag i wrap the bike in bobble plastic and add some extra padding on dropouts and brakes...
just my 2 cents