Before going we had lots of concerns about how the airlines would treat our bikes, would we be charged extra, what's the best way to pack them, etc...

We flew SAA domestic from Cape Town to Johannesburg and back with the bikes in regular bike-boxes, the kind you can get from any bike shop. The boxes are too big to go through the regular baggage-handling system on arrival, so you collect them at the baggage counter. The boxes are counted as part of your ordinary baggage allowance, and there is no specific extra charge. We were overweight in both directions (7kg flying to Joburg, and 14kg coming back) and we weren't charged any extra amounts.

For the leg from Johannesburg to Zurich, and on to Amsterdam, we flew Swiss. The same rules applied, box it and fit it into your regular baggage allowance (20kg checked-in and 7kg hand-luggage). Again we didn't attract any extra charges.

Mostly the airline personnel were pretty accomodating with handling the boxes, although they are awkward to navigate around crowded terminal buildings.

Apparently different airlines have different rules for how to pack your bikes. I believe that both British Airways and Air France require the bikes to be boxed, and they in fact sell the boxes near the check-in counters should you not have (probably not a good idea to leave it until this late though!) Chatting to various people we met along the route, and others that have taken bikes overseas, some have boxed them like ourselves, whilst others have simply bubble-wrapped the bikes and wheeled them in. Their logic being that if the handling staff can see that it is a bike they will be more careful with it, and pack it on top. Those who've done it this way seem to swear by it, but it obviously depends on the rules of the airline too. Our bikes emerged from their boxes completely unscathed so I guess the choice is personal. I have also seen bikes wheeled straight onto SAA domestic flights, covered with a little bubblewrap.

Hope this helps!