The battle is on in Barcelona, Spain's popular Mediterranean city where two airlines have started competing for passengers in the emerging trend of low-cost, long-haul flights. The first flight operated by Level - a new carrier created by IAG, the parent company of British Airways and Spain's Iberia - took off Thursday from El Prat airport for Los Angeles. The airline also flies to San Francisco, Buenos Aires and Punta Cana in the Dominican Republic. Meanwhile Norwegian, a pioneer in cheap long-distance flights, begins Monday flights to New York, Los Angeles, Miami and San Francisco. The airline will make Barcelona its fifth hub for such flights after London, Paris, Bangkok and Amsterdam. Altogether, 22 low-cost transatlantic flights will take off every week from Barcelona, breaking into a market that until recently was the preserve of traditional major airlines.

But with the emergence of a new and more fuel-efficient generation of aircraft and the collapse of oil prices, low cost carriers such as Norwegian and French Blue are increasingly operating transatlantic flights from European airports such as Paris or London.

Barcelona, a huge tourist magnet, is well placed to ride on this new wave, given that it is Europe's number one hub for low-cost flights.