By Jennifer Ablan (Reuters) - Ray Dalio, founder of the world's largest hedge fund Bridgewater Associates, says the next big monetary and fiscal move should include an airdrop of money from helicopters to stimulate the U.S. economy. He may not be entirely serious about "helicopter money." But in a client note sent out this week, Dalio said the U.S. Federal Reserve's ability to boost growth through lowering interest rates and quantitative easing is "weaker than it has ever been." "Monetary Policy 3" or MP3 will have to be directed at spenders more than at investors and savers, he said. Dalio,...