Go with what the Chairman wants. Appearances ARE important, and you don't want to be the reason the others traveling with you think your company is "cheap" or "not doing well" and "forced" you to fly economy. People who don't like that you flew business while they can't should mind their own business. With responsibility comes some perks, and some duties. It is a perk to fly business or first, and your duty to properly represent your company to a client.