On the original vinyl version of the album, "Goodbye Blue Sky" occupied the last slot on the first side of album one (The Wall
was a double album). In an interview around the album's release, Waters described the song as being a recap of the first side of album one, summing up Pink's life to that point. As Waters says, in it's most simplistic form "it's remembering one's childhood and then getting ready to set off into the rest of one's life."
Robert - New Bern, NC