The so-called methodology and framework agreement was signed with most of the unions representing ground staff, cabin crew and pilots, Europe's biggest airline by revenue said in a statement on Tuesday. The deal is "a first step in Air France's transformation process" and paves the way for a new set of labour agreements to be concluded by June, the company said. Air France-KLM swung to a 353 million euro operating loss last year, squeezed between soaring fuel costs and weaker pricing as Europe's economic slowdown hurt demand. The company is seeking 2 billion euros in annual savings aimed at reducing net debt to 4.5 billion euros by the end of 2014.