Getting between Spain’s major cities is most easily accomplished by air, as Spain is one of the largest European countries in size (194,896 square miles). Low-cost airlines are rife in Europe and Spain is no exception.
Some examples of low-fare airlines are AirEuropa and Spanair; flights from Barcelona to Madrid start at 19€. Iberia sometimes offers fares under 30€ (taxes and departure fees may not be included). These deals are often available, even if you book only a couple of weeks in advance; but you have to be flexible with departure times (mid-morning or mid-afternoon are often cheaper).
If you have any trouble with an airline that flys within the EU, you might like to know more about your rights as a passenger. Click here: EU laws for a direct link to the EU portal. This website provides the official complaints form, to be sent to your airline or the national enforcing authority for your destination as well as guidance on how much compensation you can expect.
All Spanish airports are listed on the following website. Here you can find deatils of desinations and airlines that serve the route: Spanish airports
