My wife and I have flown several times with a pair of Surly Travelers Checks. They aren't as quick and nimble as a Cervelo RS, but they're comfortable, fast enough, and adaptable to whatever kind of ride we're doing. They've had fenders, aerobars, racks/panniers, lights, (not all at once), and other accessories. It takes me about 45-90 minutes to disassemble/pack or unpack/assemble the two bikes. So far we haven't had to pay baggage fees for the S&S cases. We considered Ritchie Breakaways, but I was worried about flying with the oversized case. In retrospect, I think Breakaways would have been fine, too.

If you have a steel or titanium bike that you like, you should have S&S couplers installed in it by a local frame builder.