From time to time I read the "She Rides a Bike" blog. The author is a bike rider (sans car) from Flagstaff, Arizona, a very bike-friendly town.
But recently she and her husband took to the air with a folding bike. They traveled to San Francisco do do a bit of sight-seeing by bike (of course).
I thought her article and all the advice was well-worth a read, especially if you are considering traveling with your bike. Her photos show how the bike was packed and how the enjoyed touring San Francisco.
Article: A Few Thoughts on Air Travel with Your Bike
This (to the left) is like the bike she took to San Francisco.