I'm heading to Europe in a few days, which means I'll be spending lots of time on airplanes and trains. I have a really excellent MP3 player that gives me about 40 hours of battery life, but I'd rather not carry yet another gadget if I can get away without it. Does anyone know what sort of battery life I can expect with the Droid in airplane mode, but playing audio? My guess is that it should be pretty good, since the screen seems to be the primary battery suck, but if anyone has solid information I'd love to hear it. Thanks!