OK, first time posting - I thought I knew what the answer was until I saw the hint, and now I've changed my mind.
Firstly, my previous guess:
A Rainbow
To those who dwell amongst soot and leaves
People on the earth
The power of flight it willingly gives
Metaphorically, directs people's imagination to "greater things"
Lines that know neither start nor end
Multiple lines of colour which go round in a circle - most of these circle (by angle) can't usually be seen because the ground is in the way
Knowledge beyond what eyes comprehend
Eyes see something that looks like it might be an object in space, but if you know about what they are, you know they are not really there
Distorted illusion of that which is true
Sunlight distorted into separate colours
Into the unknown it will see you through
Sometimes seen as 'bridges' to mythological places, or that something lies 'over the rainbow'
False Shadow of an Orb:
On the opposite side from the Sun (Orb), and a trick of the light
Secondly, having seen the hint:
A Map (if you want specifics, maybe a Mercator projection)
To those who dwell amongst soot and leaves
soot and leaves = pencil lines on paper
The power of flight it willingly gives
Metaphorically, directs people's imagination to distant lands
Lines that know neither start nor end
Lines on a map can continue indefinitely
Knowledge beyond what eyes comprehend
Shows details of places that you can't currently see
Distorted illusion of that which is true?
converting a surface of a 3D earth onto a 2D map will involve some sort of distortion
Into the unknown it will see you through
can be used to navigate to a place you have never been to before
False Shadow of an Orb:
A Mercator projection is made by projecting a light source at the centre of the earth onto an infinite cylinder wrapped around it and touching at the equator