Aircraft is a machine that counters the gravitational pull of the earth by using either static lift, dynamic lift or downward thrust. Common aircraft include airplanes, helicopters, gliders, etc. Different aircraft have different methods of lift. Aerostats use buoyancy for floating in the air, while airplanes produce dynamic upthrust through aerodynamic lift or powered lift in the form of engine thrust. Aircraft can be classified as unpowered and powered aircraft. Unpowered aircraft include gliders, balloons and kites. Powered aircraft include propeller aircraft, jet aircraft and rotorcraft. The study of aircraft and their engineering is studied under the domain of aerospace engineering. It integrates the technological and engineering principles of aerodynamics, propulsion, avionics, structural analysis and manufacturing. This book traces the progress of aircraft engineering and highlights some of its key concepts and applications. It includes some of the vital pieces of work being conducted across the world, on various topics related to this discipline. This book aims to equip students and experts with the advanced topics and upcoming trends in this area of study.