Copy this command into a Command Block and activate it. (Place it in the northwest corner of chunks that will always be loaded.)
If you take a Iron Chestplate named Jetpack on and hold a lever named Control in your hand then you will fly.
You need fuel to fly so you can toss Coal (300), Charcoal (150), Blaze Rod (600),or Blaze Powder (300) onto a Gold Block. (The number after the name is how much fuel it will give. You need 20 fuel per second you fly.) (You can only toss 1 item at the time or a hole stack.)