At least six U.S. airlines canceled more than 40 flights into and out of Mexico City and Toluca airports Thursday after the Popocatépetl volcano spewed out ash, steam and glowing rocks, airport officials said. Mexico City airport spokesman Jorge Gomez said U.S. Airways, Delta, United, American and Alaska Airlines canceled 47 flights as a precaution. But he said the airport otherwise continues to operate normally and that by Thursday afternoon no ash had reached the area, about 40 miles (70 kilometers) from the volcano. …