Can it be what you're listening to inside your head? I usually don't have music on while I'm at this computer, but I almost always have a song running through my head.
Right now it's a song from The Postal Service, "Recycled Air," with great lyricas about flying on an airplane.
"I watch the patchwork farms'
Slow fade to the ocean's arm
And from here they can't see me stare
The stale taste of recycled air
Ba-ba-ba-ba, ba-ba-ba-ba"