Therefore, passengers can be relatively more sensitive to the cost of the air travel price, even though it is only one component within the overall cost of travel. Air travel itself is a derived demand, based on the demand for passengers to travel to another location for business or leisure purposes. The other components of the journey cost are derived from the decision to travel and are essentially complementary goods to air travel (i.e. they have a cross-price elasticity to air travel prices of less than zero).