With its undulating roof and luminous halls, Terminal 4 at Barajas airport heralded a new age of airport design when it opened in February. The vast Madrid airport terminal, with 67 stands, also ushered in an era of intense competition for the Spanish skies.

Low-cost carriers swooped on the extra capacity and now they are drawing up the battle lines in Spain, which is on track to receive 58m foreign visitors this year.