Can somebody suggest books on building RC airplanes Electrical or Nitro
Siddharth

There are lot of books which one can go through, but in the age of internet, you have more information at your fingertips than you could ever assimilate.
Then there is an old Hindi proverv, "Pothi padh padh jag mua...." I would suggest go out meet people, talk to them, watch them, ask questions and apply your thought. Meanwhile read up whatever you can on internet and then co-relate what you have read and what you see.
For starters if you can get books by Gordon Whitehead and David Boddington, it would help you no end.