Sometimes you can "work" with the gate agent about the cost of shipping your bike. My former exchange student, who is here now, racing, told the guy at the Delta gate in Berlin that he kept the weight of the bike/case under the limit and the agent changed his mind and said, OK, won't charge you." Of course, his bike IS super light. My son did not have such a good experience shipping his bike to Tucson via UPS. It was scratched and something was broken (can't remember what). They came out and looked at it and decided not to pay to fix it. This was a very expensive custom bike, only a few months old.
If you travel a lot, get a folding bike. My husband has a Bike Friday that he takes on most business trips. I plan to get one when i stop working and can travel with him.