American composer Aaron Copland discusses the influence of Jazz on his musical style:

was a very important influence at one time. I wrote a Piano Concerto in 1927 which was largely based on jazz materials. Jazz, of course, is for us a very typical American musical expression, which we have not so successfully been able to do in the field of serious music. So that to use jazz materials seemed a quite easy way to sound American right away without any effort. On the other hand, to use jazz materials in a work that lasts twenty minutes, and has to make musical sense from beginning to end, is quite different from writing a three- minute song in the jazz idiom. So that I became quite fascinated by the idea of using jazz on a larger canvas ― larger frame around the canvas ― in a more important way, you might say. And I was also anxious to write serious concert music which everybody could recognize as the music of an American. That was not so common in the twenties. We had MacDowell but we didn’t have many composers who were immediately recognizable even to ourselves, certainly not to foreigners, as typically American serious concert music. I found that the use of jazz materials, though limiting you somewhat as to the nature of the emotional context of the music, did solve the problem of how you write a serious concert music which everyone will recognize as being that of an American composer. That was my fascination with jazz.

Cited in: Dickinson, Peter (ed.) (2002) Copland Connotations: Studies and Interviews. Rochester: Boydell Press, p. 192.