SPAIN The F-18 Spanish fighters that have been patrolling the Libyan skies under NATO's Unified Protector mission, have thus far used some 5 million litres of fuel, every bit of which must be returned to Italy, the 'host' nation. Sources in the Spanish Air Force (Ejército del Aire, or Army of the Air) say that this is the usual procedure on NATO missions. Apparently, the country from which the mission is directed must provide the fuel needed, and have it returned in kind -not paid for- when it says so. The F-18s each use 3,000 litres every hour in flight. By the end of July Spain's participation in the Lybian mission cost €57.4 million; each month costs €14.4 million from the public purse, which is about half of what it costs to maintain Spanish presence in Afghanistan.