Fewer Americans filed for jobless aid last week as lay-offs remain low despite a number of uncertainties that continue to cloud the economy.US applications for unemployment benefits for the week ending May 16 fell by 3,000 to 209,000, the Labour Department reported Thursday. That is fewer than the 213,000 new applications analysts surveyed by the data firm FactSet had forecast.Weekly filings for unemployment benefits are considered a proxy for US lay-offs and are close to a real-time indicator...