Germany to Mallorca for one euro, to Nice for ten. With bargains like these, low-cost airlines have won new customers in recent years: people who otherwise could not afford to fly. But the days of dirt-cheap air travel may be over. Now airlines are now trying to increase revenues with additional charges; for example for seat reservations, luggage transport or accepting credit cards. Because unlike established carriers like Lufthansa, very few low-cost airlines bought reserves of fuel as insurance against oil price increases. Fuel has become the single most important cost factor for airlines. Dan Hirschfeld went behind the scenes at Germanwings airlines to see how such carriers try to deal with the crunch.