Has the Kindle menu design changed in the last day or so? To switch Wi-fi on or off, you previously pressed the menu button at the home page and the option to turn off or on was the top menu item. Now you have to go to settings and select "Aeroplane Mode". This must have changed in the last day or so because I downloaded an e-book a couple of days ago and used the old method to turn wi-fi on. I would imagine that many users are going around with wi-fi on permanently and thus using excessive battery power if they were not aware of this.