The yields on many Treasuries, which are considered virtually risk-free if held to maturity, now dwarf the S&P 500's dividend yield, which recently stood at about 1.8%, according to Refinitiv Datastream. American Airlines AAL.O, United Airlines Holdings UAL.O and Delta Air Lines DAL.N each lost more than 2%. By Noel Randewich and Ankika Biswas Sept 29 (Reuters) - Wall Street ended sharply lower on Thursday on worries that the Federal Reserve's aggressive fight against inflation could hobble the U.S. economy, and as investors fretted about a rout in global currency and debt markets.