The concept the airlines are employing is called market segmentation. It's legal and they have the right to do it. The concept you seem to be referencing is som

The concept the airlines are employing is called market segmentation. It's legal and they have the right to do it. The concept you seem to be referencing is some generic measure of product utilization. The office analogy is wrong. A better one would be the person who tells MS they are a student but uses Excel in their business. The train analogy is backward, would you intentionally buy a ticket to a more expensive destination if your intention were to get off early?