I just flew with my bike. It has S&S Couplers and I have the 29"x29" hard case they sell for coupled bikes that avoids extra baggage charges. I watched the person behind the airline counter take my bike, put it on the conveyor belt, and then give it a shove so it fell over. Seems to have survived that (though I haven't ridden it since so my fingers are still crossed). The S&S coupled bikes get packed with padding on every tube and anti-crush posts inside the case and bridges in the forks and dropouts.