How do you turn on free flying in minecraft?

Answer 1

In order to fly you must be in Creative mode. Creative mode can be entered by using the command `/gamemode [yourusername] 1` Once in Creative, simply double tap the jump key (spacebar by default) to begin flying. Hold space to ascend, and crouch to descend.

Answer 2

In 1.8/1.9 creative mode, you turn on flying by double tapping the space bar. To move use W A S D keys as you would for normal movement, space key to ascend, and shift to descend.