Once you are in the air, things will feel smooth. You will hear the humm of the engines, but that's normal, nothing to worry about. I actually find it relaxing. If there is turbulence, you might feel the plane wobble a little bit (usually up and down) but remember, planes are designed to withstand this, so take a deep breath and try not to think about it. It might give you a few butterflies in your stomach though. After a few minutes, you will hear a ding. This is the captain letting the flight attendants know that the plane has reached the cruising altitude. At this point, the rate of ascent will decrease. You will also get an announcement that it's OK to use portable electronic devices at this time.
To entertain yourself:
*Read a book, magazine, the paper, or do a puzzle (such as crosswords or Sodoku if you like those).
*Listen to music using an iPod, MP3 player, or CD player.
*A laptop is good to have as you can play games on it, connect to the internet, and get any work done that you may have. (You have to have a WIFI card in your laptop and the airline will charge you to connect to the internet) or watch DVDs.
*Try talking to the people next to you. Sometime you will meet some really interesting people, and forge friends