So...if an airline operator says "I need to get a yield of £50 a seat to make it work"...what is he looking for????
Think you are assumming that there is a single definition and everybody would sign up to same definition and treat it exactly the same..........its like saying what is the ticket price.
Example would be BA stating its getting a yield of £120 per passenger on LHR-JFK thereby sending a message that others would pick up and decide to go after but given that AF may measure yield in a different way it could mean AF would get a yield of £40 or £180, an extreme example but companies want to hide as much as possible to keep competition away.
Its why when an Airline listed on a couple of Stock Exchanges states different profit figures to each as laws will be different in each country.