Hazardous FlightFlying a mile high above the rolling hills of the countryside, Terry Mapes suddenly put Skybird, her little blue-and-gold monoplane, into a series of loops. She was feeling good, her brown eyes were keenly alive and her slight boyish figure sat erect as she handled the controls of her plane. And being a young and lively girl, she wanted to turn somersaults in the sky to express her joy.Her twin sister, strapped in the rear cockpit, spoke to her through the earphones, "Quit your circus stunts, Terry, and keep going! We've got a long trip ahead of us.""You guessed it, Prim. That's why I'm feeling so full of pep!" answered Terry and her voice died away as she put Skybird into another loop among the clouds.The next minute her plane was on an even keel and Prim repeated: "Terry, will you stop clowning? Save that pep! You'll need it before we get to South America."