1. Read a book. Bring your favorite book or from your tablet or Ipad.
2. If you are seating with a person who seems to friendly, you can say hello and maybe start a conversation if you receive a positive response.
3. Write your things to do list. Make use of this time to check on your tasks or activities when you get off the plane whether it is a business or a holiday trip.
4. If you are in the window side, appreciate the beauty of nature. This is the only chance you can be up close on clouds and experience being up there.
These are a few things to note, there are many ways to keep yourself busy while waiting for the "touch-down" on your destination place.