Why do passenger planes fly so high in the atmosphere?

Question

I know that commercial planes fly at over 10,000 metres in the air. Why cant they fly closer to the ground? Has it got something to do with airflow? pressure? updraft?
It is something that has always had me wondering

Answer 1

The air at the higher altitudes is thinner so the aircraft can work more efficiently at these altitudes. This means it is much more fuel efficient then at lower altitudes. Also this will usually get you above any inclement weather and make the trip much more enjoyable for the passengers.

Answer 2

1

Answer 3

It is not that jet engines perform better at higher altitude, but rather they are more fuel efficient. Performance is far greater at lower altitudes. Just think about when you are taking off and the airplane accelerates quickly and pitches way up. There's lots of extra thrust down low to allow that.

The fuel/air ratio remains somewhat constant through the climb. As altitude increases, the air thin outs and therefore, so can the fuel flow.

Airlines try for the most efficient routes and altitudes as possible to save money. They do however change altitudes in flight (higher or lower) when needed for weather and turbulence avoidance.

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And a note about the jet stream, it is relatively narrow and always curving, so the time an airliner would spend there is very short. And another thing, it flows mostly west to east isn't the U.S. so a westbound flight would be at a disadvantage. Airlines still fly high whether traveling East or West.

Answer 4

sometimes it's the airflow, but it's the thinning of the atmosphere that keeps it going. remember, draft has a huge impact on a plane traveling about the speed of sound, so the thinner the air, the less draft you have to work against

Answer 5

The modern aircraft fitted with jet engines perform better at high speeds and high altitude. The density of air is less at high altitudes and the drag is less, because of the rarefied atmosphere. The atmospheric disturbances and turbulence is less at high altitude.

Answer 6

Turbulence is much, much worse at lower altitudes. Higher up you go, the less resistance, from cross winds etc. So less drag, better gas economy, etc. But the big plus is much less turbulence. Plane easier to control, passengers happier.

And I agree with the poster above me about the top guy...speed of light?

Answer 7

Less resistance, use jet stream, overfly weather, less likely to be
brought down by my Uncle Ned who shoots rifle at any aircraft;
he was bombed rather too many times by the USAF in Korea.

Answer 8

Mostly to do with air resistance, therefore fuel efficiency. There isn't much to push against in the upper atmosphere, so fuel costs go way down.
There are also issues with noise in populated areas, but this is minimal compared to fuel savings.

Answer 9

Because transport aircraft use gas turbine engines which are more efficient at the higher altitudes, generally around 36,000 feet.

Answer 10

there is less air up there, AKA, less drag, so they can go faster. They also get above the clouds, and get into the jet stream. Theyre also way out of the way of anything else (like light planes and such), and are much quieter for the ground.

and the guy above me is totally clueless.