For those who are still interested in deadtreeware a handy item is a handy little book, a bit bigger than 3" by 5", that goes by the name of: "Pocket Ref" by Glover:

http://www.sequoiapublishing.com/pdt_pocketref3ed.htm

It has pretty much everything in it. If I was going back in time with only what I could fit in my pockets this would go with me. Very handy for the codger who still likes books.

No restrictions for in-flight use, no power needed. A power outage, or, god forbid, an EMP won't make it into a doorstop.

Of course the next question is: How do you do your complex calculations without power or electronics? You could use pencil and paper for calaculations or ...

Let me introduce you to a fancy bit technology, the slide rule. It was all the rage, and a badge of honor for scientists and engineers well into the sixties. The ladies near about fell over for a man who was proficient with a high precision 12" slip stick.