WASHINGTON (Reuters) - U.S. airline passenger traffic fell 63.3% in January, as the industry recorded its worst month since September amid COVID-19 concerns, the U.S. Transportation Department said Friday. The largest U.S. airlines carried 25.8 million passengers in January, compared with 70.5 million passengers in the same month last year. For all of 2020, U.S. airline passenger traffic fell by 60% to 368 million passengers, the lowest since 1984, as the industry reported pre-tax losses of $46 billion. On Thursday, President Joe Biden signed legislation that awards airlines another $14 billion payroll assistance package.