Pop flies, also known as fly balls, are a type of batted ball in baseball. They are hit high into the air and usually caught by an outfielder for an out. The term 'pop fly' is derived from the sound made when the ball is hit. The crossword solution for the term 'pop flies' is SWAT, which stands for 'short, weak, and timid'. This term is used to describe a pop fly that is hit with little power and does not travel far.