Your holiday's booked and you're off to ride your bike in foreign climes. The tricky part is taking your bike on a plane with you.
You need to pack it in it in a way that means it can withstand the baggage handlers' manhandling, and make sure it will come off the plane in the same state that it went on...
What to pack your bike in
Most airlines require bikes to be either boxed or bagged for travel. A decent bike bag can cost anywhere between £60 / US$90 and £500 / US$900, which we'd say is a worthwhile investment if you intend to travel with your bike often, or even if you regularly transport your bike by train, bus or car. It's also an excellent option for long-term storage.
Many bags come with handy wheels, such as the Chain Reaction Cycles Pro Bike Bag
A cheaper option is to pack it in a cardboard bike box, which should be available for free from your local bike shop (although some charge). These are cheap and offer good protection but there's a limit to how many times you can fold them down and build them up again.
Hard bike cases offer good protection, but are a real pain to stash in the back of a hire car or hotel wardrobe.
How to pack your bike
To pack your bike, you'll need the relevant bike breaking-down tools, pipe lagging/bubble wrap, zipties/toe straps, a rag, some spare cardboard and duct tape. If you can get the plastic fork/rear end spacers from the local bike shop then all the better.
Pedals, seatpost and saddle
Take off your pedals, tape them together and tape the threads, then carry them in your regular luggage if you don't have a bag with side pockets. Don't leave these items loose in the bike bag. Remove your seatpost and saddle, or lower it to its minimum height (as long as this doesn't scratch the post). Make sure the clamp is either lightly tightened or removed and carried in separate pocket.
Remove the wheels, deflate they tyres slightly (don't deflate them too much as this can cause rim damage if the bag gets dropped). Take out the quick-release skewers and tape them to the spokes, or stash them safely in any bag pockets available. If you have plastic fork/rear triangle spacers (which come with new, boxed bikes and forks – your local bike shop might let you have some) put them in place.
Remove the rear hanger and derailleur, and then tighten the hanger bolt so as not to lose it in transit. Wrap the mech in bubble wrap or a rag and strap it between the rear stays, so that the hanger doesn't get bent or the chain slap around against the frame.
Depending on the size of your bike and bag, either turn your stem sideways and turn your bars downwards and under the top tube on the chain side (padding the top tube and strapping the bars against it), or, if the bag is too small, remove the bars and strap them in that position (try to leave the stem on or strap/ziptie your forks and head set together to prevent the loss of headset parts).
It's a good idea to install a fork protector
Cranks and chainrings
Box it up
If you are using a box then place the bike inside, chaining downwards, and then put in both wheels, one to the front and the other towards the back of the bike (both chain side) with sprockets in the gap in the frame. Pad the contact points/or put cardboard sections in-between and ziptie/strap the wheels to the frame. Seal the box with duct tape and be sure to write your contact/destination details and flight info on the box.
If you're using a cardboard box, make sure to tape it up securely
Bag it up
Unless your bag has a hard base then the bike goes in the bag upside down to protect the chaining. If the bag has padded wheel bags then use these and place the wheels on either side of the bike, staggered for less bulk. If you have no wheel bags then follow the padding procedure as with the box, but strap the wheels on the chainside of the frame, staggered for less bulk.
It does not pay to padlock the bag, as security may wish to open it – but a ziptie between the zips will aid security and can easily be cut when you arrive.
A final tip
Always check your bike for damage/loss before clearing customs, otherwise the airline's liability is limited. Be sure to get written confirmation of any damage from baggage handlers too.