I really don't like renting cars when I fly to other cities. The cars usually suck and it's expensive. So the logical solution is to take one of my bikes with me, but that's not as simple as it used to be. To bolster their profits airlines have started charging bag fees and evidently they see cyclists as cash cows. Delta will charge you $150 each way to transport your bike. Southwest is more reasonable at $50 each way but neither is as good as Denver based Frontier. Frontier charges just $20 for economy ticket holder to fly with a bike that's less than 50 pounds.
However, there's a way to avoid these high fees through the magic of folders. A boxed folder will usually be treated like any other checked bag. But until I get my Brompton, if I want to fly with my bike I'll have to pay.
Bicycling Magazine has more details.