Air travel to and from Barcelona is frequent, inexpensive and very reliable within Europe. The three main airports are Barcelona (El Prat), Reus, and Girona, although Reus and Girona are a relatively significant distance from the city. These last two are where the budget airlines are based, but if you choose to use these be careful of extra costs like unexpected taxis or hotel accommodation if your flight lands after the last buses and trains have departed for the night.
If you live and work within the boundaries of Barcelona proper, there is really no need to own a car. Barcelona´s inner suburbs are notoriously difficult and expensive for parking and you may be better off without the headaches of full-time car ownership. If, though, you would like to venture out to explore Catalunya (strongly suggested) or you would like to take advantage of the open-air markets to stock up on fruit and vegetables, you will need access to your own private transport.
Most locals own some form of private transport, even if it’s just a motorcycle, which is easier in terms of parking and moving about the city.
If you prefer not to own a car, it might be in your best interests (and possibly cheaper) to hire a car once a month, to take weekend excursions or bring home the bulk buys. Pepe Car is the best value local car hire company and, of course, Barcelona is well served by the big players like Avis, Hertz and Europecar.
Public transport in Barcelona is very good. All of the districts and neighborhoods are well-connected by metro, train and bus. Taxis are a good option, too, although they can get expensive if you use them during peak times (there are extra tariffs). Also, in 2007, Barcelona launched its Bicing, or community bicycle program (like many other major cities in Europe).
If you need to get to outlying areas that are not heavily trafficked by tourists, you should either plan your trip carefully as public transport will be infrequent at best, or simply hire a car.