"An Irish Airman Foresees His Death" is a poem by Irish poet William Butler Yeats (1865-1939)
 written in 1918 and first published in the Macmillan edition of The Wild Swans at Coole in 1919.

I know that I shall meet my fate,
Somewhere among the clouds above;
Those that I fight I do not hate,
Those that I guard I do not love;
My country is Kiltartan Cross,
My countrymen Kiltartan's poor,
No likely end could bring them loss
Or leave them happier than before.
Nor law, nor duty bade me fight,
Nor public men, nor cheering crowds,
A lonely impulse of delight
Drove to this tumult in the clouds;
I balanced all, brought all to mind,
The years to come seemed waste of breath,
A waste of breath the years behind
In balance with this life, this death. 

The texts are from:
https://en.wikipedia.org/wiki/An_Irish_Airman_Foresees_His_Death
More information about W.B. Yeats:
https://en.wikipedia.org/wiki/W._B._Yeats