[mastercoms]

You should be able to fly in creative mode.

[bgrohman]

Take a look at the Glowstone configuration docs here:

https://github.com/GlowstoneMC/Glowstone/wiki/Configuration-...

It says for the "allow-flight" option that the default is "false" and it's "Currently not implemented."

I tried setting it to "true" anyway, but it still didn't work.