List of Reasons Why Airplanes Don’t Fly over Tibet or (other mountain ranges higher than 20,000 feet above sea level).
The mountains in Tibet are very tall. Mt. Everest is at the border between Nepal and Tibet. There are many mountains over 20,000 feet above mean sea level. Though most commercial aircraft can fly higher than the mountains, there’s still a chance you can crash into the mountains.
It’s a terrible place to be if you need to make an emergency landing. You’ll crash into the mountains.
If a plane loses cabin pressure, general procedure is to descend to an altitude with breathable oxygen. If this happened over Tibet, there’s a good chance you’ll crash into the mountains.
If you lose an engine, most drift down procedures call for a descent to approximately 20,000 feet. At this elevation you’ll crash into the mountains.
There’s not a ton of major travel hubs in or around the Tibetan plateau. Therefore, there’s not a huge need to fly over Tibet. So airlines don’t do it. They don’t crash into the mountains.
Clear air turbulence. There’s a higher probability of clear air turbulence caused by the Himalayas. Which can cause you to crash into the mountains.