Why Airliners Don’t Fly Above 40,000 Feet

Why don’t airliners usually fly above 40,000 feet? At first, flying higher seems like it should make aircraft more efficient. The air is thinner, drag is lower, and fuel economy can improve. But as airliners climb higher, the same thin atmosphere that reduces drag also starts creating problems for the wings, engines, pressurisation system, and safe operating speed range. In this episode, we break down: Why Higher Altitude Helps: How thinner air reduces drag and improves cruise efficiency. Why Wings and Engines Struggle: How lower air density affects lift, jet engine thrust, and aircraft performance. The Coffin Corner: Why the safe speed range can become much narrower at very high altitude. Cabin Pressurisation Limits: How higher altitude increases the pressure difference across the fuselage. Why 35,000–40,000 Feet Works So Well: How airlines balance fuel efficiency, performance, safety, and operating cost to find the ideal cruising altitude. 🛡️ Protect Your Online Privacy with NordVPN: Whether you're streaming, researching, or browsing on public Wi-Fi, keep your data encrypted and secure with next-gen speed. 👉 Get the best deal on NordVPN here: https://go.nordvpn.net/aff_c?offer_id=612&aff_id=155415&url_id=14830 (Includes a 30-day money-back guarantee!) Subscribe to Simple Concepts Explained for clear breakdowns of aircraft, aviation, trains, engineering, transportation, infrastructure, and the technology that keeps the modern world moving.