$400 is an annual wage for much of the world. if you can fly in a plane you are rich, it's just a question of how rich you are.

In the 1970s a transatlantic return was about $3000 in today's money. You can get a business class bed for that now. If you could afford to travel in economy in 1970, you can do it in business today, and business today is far above first class in those days.

If you work for a company that insists on flying you in economy and you don't like it, it's time to move job.