FOSS gamedev and creative worlds

When I try to fly on creative mode, it says I do not have privileges for it, but singleplayer mode shouldn't have privileges. Anyone know how to give them to myself? Running version 4.2

maybe following steps may work for you.

type /grant singleplayer fly,fast in the chat-box (press t-button)

0.4.2

And like cHyper said;

/grant singleplayer all

will work.