In situations where one component of
a package can be substituted for an adequate
alternative then the price elasticity for that component
can be much higher than suggested by the price
elasticity of the overall package. For example, changes
in an air travel price could result in the passenger
changing to a different airline, route or another
transport mode while still undertaking a similar journey.
Therefore, the elasticity for the overall journey cannot
be inferred from the air travel price elasticity and must
instead be estimated on a separate basis.