I'm sure technically it would be more PC to forego all air travel, especially for a Green, Eco loving Prince, but it's just so difficult to effect in practice, for anyone. I'm satisfied with CH's official explanation. Recovering from a hysterechtomy(sp?) is a terrible experience, which I am too young to know from personal experience, but I have seen enough intimate family members experience it to understand that the Duchess can be excused for opting for the most convenient means of travel. I think the Prince seems to be cutting back where possible. It is good of him to forego air travel to polo matches, hehe!