American Airlines AAL.O rallied 3% after it forecast positive cash flow. By Noel Randewich and Devik Jain July 14 (Reuters) - The S&P 500 ended with a gain after briefly hitting an intra-day record in a choppy session on Wednesday, as investors balanced worries about inflation with reassuring comments from Fed Chair Jerome Powell. U.S. monetary policy will offer "powerful support" to the economy "until the recovery is complete," Powell told a congressional hearing in remarks that portrayed a recent jump in inflation as temporary and focused on the need for continued job growth.