Planet Minecraft

I need help with certain plugins,I have Essentials and I have set it up so players can fly. The only problem is that how do I set it up so that the gamemode and fly commands can be constant.

Every time I warp to another world,I have to use the commands every time because they get reset. What do I do to fix this problem?

Also I need to know what I can do to allow players to build,but NOT destroy blocks in a certain world. I have a preset world made and I need to know how to allow players to build around the world but not destroy the original world's blocks.

They should only be allowed to build and destroy their own blocks. Anyone know how to do this?

try simplefly on bukkit for flying but idk about building and destroying sorry :/

if you give people the essentials.fly permission then they should alwsys be able to fly and as for the worlds get permissionsEX and modifyworld (theyre bundled) then in the permissions give the modifyworld.* permission to people only for certain worlds... or you can download worldguard and make regions where players cant build