Thanks a lot for your answers.
If I read correctly your answer to my question 1, there is no market research tool like there is for the routes to predict revenue from lunch/dinner/breakfast? It is all guess, and check in misc to see what improves?
Another daft question: I am thinking to buy my first aircraft. When I look on the used market, there is a table that gives a value for the aircraft and a sale price. Then, when I click on the aircraft I am interested in purchasing, there is a more detailed page about the aircraft, including a table showing a value for that aircraft. But that value is different from the value shown in the first table. What are both values supposed to mean? Is one the value for a new aircraft, and the other an estimated market value for the given aircraft?
Finally, if you decide to retire an aircraft, rather than selling it (because you think you won't be able to sell it anyway), how do you do?