The late, popular folk singer Nick Drake wrote a song titled "Saturday Sun" which appears on his album Five Leaves Left.
Samples/Lyrics
Throughout the song, there is an underlying drone which sounds like a cabin of an airliner during travel.
What sounds like a flute line at :47 and 2:51 is actually a reversed electric piano sample.
At around the 0'16"00 mark, there is an indistinguishable sample right before the guitars begin. When this sample is reversed and slowed down by about 30%, the word "hell" can be heard.