This song has nothing to do with lsd. In a one hour documentary with David Gilmore and Nick Mason, they talked about the song and chuckled about all of the different meanings this song is supposed to have. Actually Nick had always wanted to get his pilots license and helped write this song while taking the classes to get it. The talking part in the middle of the song is actually recordings of Nick and his instructor while in flight. Come on not everything is about taking drugs.