7From hot-air balloons to stealth aircraft that can hide from radar, machines that fly in the sky are amazing feats of technology. They're made possible by developments in engineering! In this volume, readers encounter many high-flying machines, including helicopters, drones, and even jetpacks! Detailed text describes the science behind how each machine works while clear diagrams aid readers understanding. Sidebars about the coolest in flying technology are accompanied by full-color, high-velocity photographs showing these machines in action.