"Battery Life: 10, or 20 hours"

is it 10 or 20 with the battery power?   

It almost sounds like they get 20 by adding a second battery.... and airlines are doing EVERYTHING they can to reduce weight.

http://news.enquirer.com/apps/pbcs.dll/article?AID=/20080331/BIZ/303310008

http://www.amtonline.com/article/article.jsp?siteSection=1&id=5280