We've done several overseas trips with bikes so far, a few times to New Zealand, also to Denmark, the Netherlands and Italy.

Airline policies vary and are hard to find. Some airlines give you a weight/extra bag allowance for bikes and some don't. The check-in staff are usually bike friendly and give you the benefit of the doubt.

We are usually a little overweight but have only been charged for excess baggage once when returning from New Zealand. We were camping so we had front panniers and camping gear and were a fair amount over the limit. They charged about $150 for both of us. It is getting harder though, airlines are enforcing the regulations more strictly and you can't sneak small but heavy items like tools and pedals into cabin baggage any more.

For the first few trips we packed our bikes in cardboard boxes from the local bike shop. The airlines sell special boxes which are larger and stronger, but they are also heavier and even more unwieldy. We stayed in the same place on the first and last nights, and arranged to store the boxes with the owners.

We put all our other stuff in the boxes, apart from cabin baggage.

Baggage handlers treat boxes roughly so there is usually some scratching and occasional minor damage. Tape up all the corners well, and reinforce the hand holes with tape. I made two straps from one inch wide webbing to make the boxes easier to manhandle, that reduced the damage. Leave the rear wheel fitted so that the chain wheel is not resting on the bottom of the box. I took both wheels off once and the teeth got bent, luckily I found a bike shop that could straighten them. You are also supposed to deflate the tires for the flight due to air pressure.

When we went to Denmark, we flew to Poland first and then continued to the UK so we didn't use boxes on the return trip, just covered the chain and turned the handlebars. Some people do that all the time and claim that the baggage handlers treat them more gently. It has the big advantage that you can just ride out of the airport.

We upgraded to proper bicycle bags for the Tuscany trip.

Note: the photograph is from the maker's web site, not our bikes

The greater access makes packing a lot easier and is kinder to the bikes. I didn't have to twist and turn things to get them through the narrow opening and it was easier to wrap bubble wrap around delicate parts. The bags are slightly smaller than the boxes and I couldn't quite get the bikes in with the rear wheel fitted. However when I unbolted the rear derailleur and brake shoes I could push the rear wheel a little further into the forks and it fitted nicely, even inside its cover. It is important to get it between the forks because that means the wheel is supporting the bike, not the delicate chain wheel.

I cut the sides from cardboard bike boxes and slipped them inside the bags. This protects the bikes and also stiffens the bags so they don't sag and topple over as easily. After packing our panniers and other stuff inside the bags I stuffed the remaining crevices with bubble wrap, I bought a large roll. I also put one inch wide webbing straps around the bags to make them easier to lift.

The bags increased the weight, particularly with the cardboard stiffening, however we were still within the 30kg luggage allowance. We also bought carry on bags that had wheels but could also be worn as a backpack. This left our hands free to wheel the bicycle bags.

I used to hate lugging the cardboard boxes around. They were hard to balance on the trolley and kept falling off. It was difficult to maneuver them, especially through doorways. It was hard to see where you were going. By contrast the bags are easy to wheel and it was far less frustrating and embarrassing. It was the first time I didn't end up with a strained back from lugging the boxes. The bags are far kinder to the bikes, there was no damage at all, not a scratch. Unfortunately the baggage handlers did manage to damage both bags on the return trip, so they had to be patched.

I'm sold on bags. I'd be very reluctant to go back to boxes even if it meant paying excess baggage.

It's a good idea to make sure you can dismantle everything you need ahead of time, so if anything has seized up you can get it fixed at the bike shop. I've had to do that twice, once for the pedals and once for the seat post. Also mark the position of everything like the saddle post height, handlebar orientation etc. to make it easier to reassemble. I use an automatic center punch to make alignment marks.

Brake and gear cables are delicate, and it is easy to strain them when you remove and refit the handlebars so make sure they are in good condition and renew them if in any doubt. Look for broken strands at the clamps. Another advantage of the bike bags is that the side unzips, you don't have to work through the narrow top of the box.