I flew with my irreplaceable '75 Peter Johnson (1st place at Le Cirque :) back to N.C. with an Trico Iron Case and they charged me $75. Coming back I decided to ship it home in the Iron Case thinking it would be about half the cost. Pretty much the same tariff with FedEx Ground as I paid flying with it; I thought it would be less. Pretty hard to do any damage to something in an Iron Case (I've flown a lot with the case).
Conclusion: Just fly with your bike and sleep easy.
Chuck Schmidt LA, CA