If you're flying with a bike - reserve a spot for the bike in the luggage hold. I know that, for example, each Delta 767 and 777 flight only has allocation for two bike boxes in coach and one in first class / business elite. This means that if you're going to an event that week, there's a good chance your bike may not make it on the flight with you. If you're connecting, this could be a royal pain.
The good news is, at least with Delta and British Airways, and at least if you're a gazillion miler, they'll let you reserve one of these spots with your reservation. The first time I requested it (through BA), it was super simple. The next time (through Delta), it took like half an hour on hold while they went up the supervisor tree to find someone who knew how to do it. They did it, though, which makes me feel much more confident about bringing the bike to the airport.
Also, to reinforce what was said earlier, make sure you check sizes with the airline. The Delta size is actually reasonably small, and varies depending on what countries you're going to / through. Make sure you check weight as well. Some of the cases alone are heavy, and excess weight charges make excess size charges look trivial.
Just one more thing that you can hopefully worry less about,