They are bedroom hobgoblins. You think you see them, but they are really ordinary things that have been there all along: brooms, draped clothing... All you are seeing are contrails. There goes an airplane? There goes a contrail...or not, if the air conditions are dry. If the air conditions are moist, the trail goes from horizon to horizon (I've seen them). And the air conditions are what prevails at 30,000 feet, not what prevails at ground level (put on thinking cap). "Lately" is a clue that upper atmosphere weather conditions are the controlling feature.