Singapore Airlines Ltd. has asked pilots to voluntarily take as much as two years of unpaid leave amid slower than expected growth in cargo and passengers, AP reported. Pilots below the rank of captain can apply to take unpaid leave ranging from one week to two years, the carrier said in a statement Friday. The airline will allow pilots to work elsewhere during their leave, it said. Singapore Airlines spokesman Nicholas Ionides said the global economic turmoil in 2009 and 2010 meant that growth in travel had slowed and the airline had more pilots than it needed. \'As it takes about three years to train a pilot to become a first officer, we could not stop recruitment and training completely,\' he said. The airline views the \'surplus pilot situation\' as temporary, Ionides said. The global airline industry is struggling with slowing economic growth and soaring oil prices. Singapore Airlines recently cut 20 percent of its cargo capacity and raised the fuel surcharge on tickets.