I think it would be helpful to players if we could use the already available calculator, to determine how much additional cost of savings we would receive or cost savings we would lose when retiring older airliners. Right now there are only two options, "Add a new fleet type" and "Retire an existing fleet type". Neither of which allows us to look at what would happen if we were to expand any of the current fleets we have.
Thanks for a great game Sami! :)