Barcelona is a large city located in Spain. The city has high ratings ranging from 150-350.
The default airport is Barcelona-El Prat Airport (BCN).
Barcelona's ratings are relatively good, but the city does not experience intense competition. For these reasons, starting your airline in Barcelona can be a good idea. The City is in a good location to make connections to European cities (London, Amsterdam, etc.) and North American ones (Boston, Chicago, etc.) Barcelona can sustain moderate to heavy competition, but it is still better to create monopoly routes.
Barcelona-El Prat Airport will often achieve maximum slot usage, but this will occur late in the game. As such it may be a good idea to purchase the airport. Additional airports should be left to the national government as they will rarely attain a status beyond Level 2 or 3.
As with most airports its size, using small planes on high-occupancy routes is discouraged. Use of medium sized planes such as the Airbus A330 may be optimal for routes to other cities around Barcelona's size. For very large cities, bigger planes are the best ones to use.