(Reuters) - Southwest Airlines Co could be forced to lay off thousands of employees due to the coronavirus crisis in the absence of an extension of federal payroll aid, its Chief Executive Officer Gary Kelly said on Thursday. "A clean extension of the payroll support program would buy us six critical months to see our way through to the other side of the pandemic," Kelly said in a video message bit.ly/33nmDqd on twitter. U.S. airlines have been pleading for another $25 billion in payroll support to protect jobs for another six months after the last package, which banned furloughs, expired at midnight.