Step 1: Go to creature arena and exit out again. You must have a creature to enter.
Step 2: Go to the place that you'd like to fly in.
Step 3: Go to your inventory. Press tab until the yellow box is somewhere around the left hand corner of your inventory, press enter. The comet will come up, click out of it.
Step 4: You shouldn't be able to see yourself, click on your inventory once more and exit out of it.
Step 5: Click anywhere in the sky. You are now flying!