Not too sure what the air carriers cost plus, never too keen to cycle from airports as always seems to be very busy highway traffic.
On the other hand, I like riding directly out of an airport. Not sure why, but I get a kick out of not using any ground based transportation other than my bike at that point.
I have done a few different options. One trip I packed the three of our bikes in airline boxes, I have used Amtrak, I have flown with my bike packed in bike shop box, I have rented a car, and I have used shipbikes.com.
All of those had their advantages and disadvantages, but all worked well in one situation or another. With the airlines increasingly becoming a pain to deal with I think I am more likely to use shipbikes.com, Amtrak, or FedEx in the future. I really liked the fact that the shipbikes box and the Amtrak box both required almost no disassembly of the bike. Shipbikes.com seems to be able to negotiate a better price than if I deal directly with FedEx myself. They also ship door to door even to and from residential addresses. The shipbikes box is a clever design, but is $99 and is only good for maybe 4 uses on average. They do offer replacement for the outer cardboard for 30 or 40 dollars. It looks like they now also ship plastic cases. The thing is that it is a bit of a hassle to deal with a case (or the shipbikes box), especially if like me you usually fly out to one place and home from another.
So far I have not found one answer that works to my satisfaction for all of my trips and just do what seems to fit the situation. On my last tour I had the luxury of being able to ship my bike to a friend's house and then back again from there. It was nice to be able to leave the shipbikes box there. Since my tour actually ended 850 miles from his house I had to take Amtrak for that short leg of the tour where my box was.
Amtrak is great if
you are going to and from locations that have baggage service and are not in a hurry if the distance is long. I found the boxes to be huge and the service to be good. The ride was a good bit longer than I could have driven it though and if there were several of us we would have probably been better off both in cost and time to rent a car.