I should say that we did borrow SF's hard case (thanks again!) to take our nice road bikes overseas. I also bought the soft case he recommended which is excellent. The hard case totally protected gaijinboy's bike - but it also was too big and heavy to enter the plane hold and make it up the conveyor belt.
We watched the baggage handlers struggle to get it onto the plane and also watched as it fell from the cabin hold onto the concrete below.. a good long fall! Gaijinboy did not enjoy that plane journey - convinced all was lost. Luckily the hard case kept it all in shape.
Mine, in the soft case, however, proved to be much less troublesome - we also watched that being loaded and it was fine - no problems at all and no damage - the padding is quite extensive on the bag i bought and we supplemented it with pipe lagging from B&Q.
We did also buy two folding bikes which we've just taken away for a week in Zagreb. One of those did get a bit bent on the plane as we were unable to find a suitable smaller bike bag for them - so ended up improvising with bubble wrap, pipe lagging and laundry bags - but nothing too serious. We do need to find a better solution though for plane travel with the folders.