When going on long trips, it seems a waste to own a phone that is damn-near a laptop and have a separate music player. The only downfall is whether the battery life can compete. Has anyone tried a long-term battery drain down, using the music player through headphones? I can see myself using this at work, or if I go on a plane. I would imagine that in airplane mode, the battery would last significantly longer. just curious if anyone has tried it.