If you're going to be in the airplane for long you might want to consider a rechargable USB battery pack to greatly extend the 8 hours the Vox will run. They will recharge any device which uses the USB to charge.
Later: As discussed below this very likely won't work. So if you do purchase such a device test it first before counting on it.
Last edited by TonyToews; 11-12-2011 at 07:01 PM.