"Only" by Rainer Maria Rilke

Anyone wanna take a crack at a brief analysis of this poem? And yes, it is for a homework assignment. I’m not gonna try and put anything over on you all. Thanks for any help you can give!
Only (by Rainer Maria Rilke)

Only when flight shall soar not for its own sake only
up into heavens
lonely silence,
and be no more
merely the lightly profiling, proudly successful tool,
playmate of winds, beguiling time there, careless and cool:

only when some pure Wither outweighs boyish insistence
on the achieved machine
with who, has journed thither be, in that fading distance
all that his flight has been.

Perhaps you would get more replies if you try posting what you think it means and get some reactions to if your interpretation is justified. Good luck.