Question

which plane would fly faster at a lower altitude a jet plane or a prop plane

I know jet plans fly at higher altitudes but would the air density allow a prop plane to beat it in a lower altitude

Answer 1

As the altitude increases, the density also decreases which means drag will also decrease.

Now, In the case of jet engines, the frontal area is pretty big so more the area, more will be the drag but the frontal area of prop engines is relatively smaller thus the drag is comparatively less. Therefore, the prop engine is more efficient at lower altitude but as far as speed is concerned, there will not be much difference so for given amount of fuel, the prop engine will be more efficient . Bu jet engine can still beat prop engine if efficiency and fuel is not an issue