By Air
We hopped to Barcelona on a SkyEurope flight from Budapest and left it on Smart Wings flight back to Budapest. Both SkyEurope and Smart Wings are budget carriers, so a return ticket with all taxes included cost us only 76 EUR per person. SkyEurope unfortunately went bankrupt since - we wonder if it was because of their (too) low ticket prices.
There are numerous low-cost airlines such as easyJet, Germanwings and Wizz Air flying to Barcelona from several European cities. On our second visit of Barcelona, we flew easyJet from London Stansted and back.
Reputable traditional airlines serving Barcelona include Austrian Airlines, Continental Airlines, Delta Airlines, Finnair, KLM Royal Dutch Airlines, Lufthansa, SAS Scandinavian Airline System, Singapore Airlines, Swiss International Air Lines Ltd and of course Spanish national carrier Iberia.
One thing to be particularly careful about when booking your flight to Barcelona (especially if it is a low budget flight) is to check whether the flight is really to Barcelona Airport (BCN) or is actually to Girona Airport (GNO), about 100 kilometres away.
Ryanair for example flies to Girona and operates buses between Girona Airport and Barcelona. The journey takes 1 hour and 10 minutes.
Video
Our Sky Europe flight 1160 from Budapest to Barcelona. Take off from Budapest, nice aerial views of Elisabeth's Bridge, Chain Bridge, Parliament, Castle Hill and Margaret Island, then landing in Barcelona.
By Train
Barcelona has good rail connections with cities in Spain and across Europe. Check RENFE (Spanish Railways) website for details.