Adapted from The Philadelphia Inquirer, December 2003 ~
Unfortunately, most airlines add a considerable fee to take your bicycle along on your domesticair travel trips, generally $80. each way. Overseas trips have been exempt, but regulations and fees are changing. Despite the airlines' efforts to drive people to their web sites, most of these sites barely mention bicycles policies. You'll have to call an agent to verify the policy that applies to your destination and situation.
Travelers who regularly take their bikes on trips should look at these two options as they are much easier and more convenient:
Travel Cases - hard and soft cases for easy packing
S & S Couplers - this option fits your bike in a normal size suitcase so it will NOT be subject to any additional airline fee. That should save you $160. per round trip! If asked, tell the ticket agent that the box contains "athletic equipment".
For the very rare trip, cardboard may do the trick, but it can be a hassle. You'll have to box the bike up yourself. Most major airlines sell reusable bike-size boxes (usually $20.) at the counter in some, but not all, airports. If you get the box in advance you won't face removing pedals and other dismantling and packing in the terminal - or the possibility of no box being available. In any case, allow extra check-in time.
If you pick up a box at your local bike shop (usually free) you will need to dismantle the bike more than if you use one of the airline's larger boxes. Cartons at bike shops must be smaller so they can travel by UPS. These boxes require pretty considerable dismantling and careful packing in order to fit a bike.
Here is information that reservation agents provided The Philadelphia Inquirer:
American Airlines - (800) 433-7300, will allow a bike under the free baggage allowance if it is within 50 pounds and 62 linear inches (box length plus height plus width). But, most adult bikes probably will not meet the 62" rule. Expect to pay $80. each way.
Continental Airlines - (800) 525-0280, charges $80. each way and has rules for disassembly and storage of accessories.
Delta Air Lines - (800) 221-1212, charges $80. each way. Packing boxes are free, but subject to availability.
Northwest Airlines - (800) 225-2525, charges $80. each way. Boxes are available in limited supply for $20.
United Airlines - (800) 241-6522, charges $80. each way and says passengers should expect to sign a limited release form.
US Airways - (800) 428-4322, has an $80. fee each way.