How does a 400-ton airplane stay in the air? Why do astronauts float but not fly away? What will it really take to live on Mars? How to Build a Sky is a beginner’s guide to aerospace engineering written for people who dislike textbooks. No equations. No jargon. No prior knowledge required. Author Carl Wang explains the science of flight using everyday objects: a spoon and a faucet, a hand out a car window, a paper plane that stalls. The book breaks down complex ideas into simple stories, from the Wright brothers’ first flight to landing rockets on drone ships. Readers will learn: The four forces that control all flight: lift, weight, thrust, and drag Why airplane wings are curved and how a kitchen experiment proves it How jet engines breathe air and why rockets carry their own oxygen Why the International Space Station is falling 24/7 but never hits Earth How pilots land safely when they cannot see the runway The engineering challenges of hypersonic aircraft and Mars habitats This book is for curious readers ages 12 and up, including students, aviation enthusiasts, future pilots, and anyone who has ever looked at a plane and wondered “how does that work?” If you appreciate the clear explanations in What If? by Randall Munroe or The Way Things Work, you will find the same approachable style here. Physics did not promise we could fly. Humans figured it out anyway. This is the story of how.