Washington (AFP) - President Donald Trump, trailing in the polls with the election just three weeks away, returns to the campaign trail on Monday after being hospitalized for Covid-19, embarking on a sprint through key swing states.As Trump heads for Florida -- the first of four battleground states he plans to visit over the next four days -- his Democratic opponent Joe Biden will be touting his economic plans in the midwestern state of Ohio.Trump, 74, who has declared himself "immune" after catching the coronavirus, plans to hold an outdoor campaign rally on Monday evening at the airport in S...