In my view, financially sound companies where the CEOs and its first line fly economy are full of s**t. I would actually question how much they really walk the talk on topics like ethics, etc. as usually the more a company talks explicitly about it, the less they practice it.
I think a frequent traveller for business reasons, regardless of seniority level, should be supported adequately by corporate travel policy. Corporate travel is a sacrifice of own personal time. Think about the nights, evenings, sometimes even weekends sacrificed being over the Atlantic flying to a meeting. If you expect me to land and be prepared to be effective, you should provide accordingly.
Only in case of financial troubles I accept the idea (and actually championed it myself) to cut back on travel costs, but when it's done just for image sake, it's complete ........ IMO.