The real story behind blackbird is quite cool...
During the U.S. civil rights movement, the Beatles were watching blacks getting mistreated on TV (sprayed by hoses, dogs, ect). A "bird" in U.k. is a word for woman. So listen to the lyrics again with with this is mind...
"you've been waiting for this moment to be free, blackbird fly..."
that's why the Beatles were great.
Yeah and the guitar accompaniment was based on Johann Sebastian Bach's Bouree (classical guitar piece).