What is meant by tourism perishability?

Tourism is a service that you are selling. Since it is a service and not a tangible good, it is perishable or in other Words you can't stock up and save it. An example of perishability in tourism would be airline tickets. Say there are 100 seats on a flight at a certain time and only 70 of them are bought. You can't use the 30 empty seats and apply them to the next flight. Instead the 30 seats stay empty and are a loss to the company. The empty airline seats no longer count and are perishable.