Basically just a song about the simple exuberant youthful innocence (both in terms of the times and the youth of those times) of the post WW2 1950's including its very early rock and roll, and the end of that simplicity, exuberance,youth and innocence as life and the music changed, as a factor of growing up with the issues of Civil rights, drugs, Viet Nam etc, with the start of the change symbolized in the song by the loss of several great artists in the 1959 plane crash.   A wonderful set of poetic images of American culture of the 1959 - 1969 decade, many of which probably have several references - but its a heck of a lot of fun, whether you try and analyze them to death or just let them flit by.