1 Introduction
The past few years have shown that airlines now earn less through traditional ticket sales, but have increased their income share with ancillary revenues. There is a general trend in the airline industry to try to find ways to generate ancillary revenue by offering additional or unbundled services. Low-cost carriers in particular make up to 35% (Spirit Airlines, 2012) of their revenue by unbundling the services of a flight ticket and charging extra for different services depending on passengers' use (e.g., baggage check-in). Full-service network carriers can also do as low cost carriers do and unbundle their products, but the question is whether their customers become dissatisfied, and whether this tactic reduces their brand value and thus makes them slip into price competition with low-cost carriers.