[10 April '06:
Here is a link[PDF} to a much longer article I wrote on this subject, it duplicates some but not all of this post.]
Questions about travelling with bikes come up all the time. They are mostly about what you have to pay to ship your bike and the pro's and con's of bags versus boxes. I've written a couple of things in the last few days that were worth adding here.
The ACTUAL Rules for British Airways (BA) can be found here:
http://www.britishairways.com/travel/bagsport/public/en_gb They key phrase is luggage allowance. If you are travelling transatlantic or to the far east many but not all class of tickets will give you an allowance of 2-pieces - What the above says is your bike travels free as one piece provided it fits within the height+width+length limits described here:
http://www.britishairways.com/travel/bagchk/public/en_gb However, most European and cheap tickets do indeed limit you by weight. Here the trick is with BA to take a large(but not oversize) sports bag, load it up with everything heavy and take this as hand luggage. Pack everything light in your bike box and your bike can travel for free(usually). However, if you overpack your bike box and make it too heavy(>32kg) they can refuse to take it.
There is a good but somewhat dated list of tips/comments/discussions on travelling with bikes here:
http://www.bikeaccess.net/BikeAccess/default.cfm For American Airlines, the rules are pretty similar to BA except more clases of tickets give you a two piece luggage allowance.
http://www.aa.com/content/travelInformation/baggage/baggageAllowance.jhtml It is unfortunate that sometimes your bike box will be measured and most(all?) do not fit within the height+length+width=62-inches restriction. I've not had this problem though.
On the comments on US Airlines, I'd observe that you've really planned badly if your transatlantic trip doesn't include a 2-piece allowance and when buying your ticket you should check into this as you can often get a different class of service with more or less restrictions, for just a few quid more. Almost all US Domestic(not part of a transatlantic connection) flights will always charge you 80 US Dollars each way to ship a bike. You can sometimes get away with this but after 6-years I've found no sure fire way of doing this for free. Also, these days at big US Airports you really, really should turn up 2-hours in advance for domestic flights to ensure your bike flys with you!
Here some other comments I've made on this subject:
For comments on why the size of the box is important before and after the airport Comments and observations on flying with bikes Finally, it is worth saying that I have seen touring cyclists just remove the pedals, turn the handlebars, let air out of the tyres and check their bikes in - no bags, no boxes, no problem.
Wiggle.co.uk sell the latest Scicon cases, you can find the Wiggle site via this
link