You might think, “Why stop at 35,000 feet? Let’s punch it to 100,000!” Great question, Captain Bold. But here’s the thing: the higher you go, the thinner the air gets. And thin air is terrible for jet engines—they need oxygen to burn fuel, just like you need it to not pass out while explaining this to your seatmate.
There’s also a sweet spot called the “cruising altitude.” It’s a magical Goldilocks zone where the air is thin enough to reduce drag (so you burn less fuel), but thick enough to keep the engines happy. Plus, at this height, you’re above most weather—clouds, rain, and even those annoying thunderstorms that make your coffee do a little dance on the tray table.
And yes, there’s a speed limit of sorts. Not a cop with a radar gun, but the sound barrier. Most commercial planes fly at about 85% the speed of sound—fast enough to make you late for a meeting in another city, but slow enough to avoid breaking windows with a sonic boom.
What about the “really high” planes?
Private jets? They can laugh at 40,000 feet. Some Gulfstreams and Bombardiers will happily climb to 51,000 feet. That’s so high that the sky outside looks like a deep, dark purple—like a bruise on the edge of space. You’ll even see the curvature of the Earth, which is both beautiful and a little unsettling. (Don’t worry, we’re not falling off.)
But the real show-offs are the Concorde (RIP) and military jets. The Concorde used to barrel along at 60,000 feet—so high that the passengers could see the stars during the day. That’s not a fun fact; that’s a glorious insult to anyone stuck in coach on a 737.
The 6 Types of Altitude in Aviation (Airplane Pilots) - Pilot Institute
And if you want to get truly ridiculous, consider the SR-71 Blackbird. This spy plane could hit 85,000 feet—over 16 miles up. That’s basically the edge of space. The pilots wore suits that looked like they were designed for a moonwalk, because the cabin outside was a brisk -60°F and nearly a vacuum. They flew so high that if you sneezed, you might accidentally achieve orbit.
