How Airplanes Work – The Basics You Need to Know. Airplanes are one of humanity’s greatest engineering achievements. They allow us to cross oceans in hours, carry passengers and cargo across the world, and connect people globally. Although airplanes are extremely heavy—sometimes weighing hundreds of tons—they can still fly smoothly through the sky. The secret to flight lies in physics, aerodynamics, engineering, and careful control. Every airplane operates under four key forces: lift, weight, th