Battery Sound volume

I want something I can use to listen to audio books on long flights. How is the volume? I want to hear over engine noise. Also. What kind of batteries does it use? I would prefer being able to keep spare batteries to exchange when they run out on long flights. Finally, when I change batteries does it keep the place and, if not, how hard would it be to find my place again?

Probably a good idea to say what player “it” is, but none of the Sandisk players have had external batteries in a long time.  You’ll get 15-17 hours off the Clip+ internal battery, a little less off the older Clips.  Volume is comparable to every other player out there unless you set the region to a country in the EU where its volume capped.