You can only use them on that island. The same applies to the jetpack and glow stick on Early Poptropica, and the flying power on Super Power Island. They do not work on any other island.
The cell phone costumizer feature does work on any island.
you get it by the glider
If you "beat" the island, then the glider (a reward for returning the notebook) is already in your item bag.
When ever you want to!
When you give Lenord Da Vinci his notebook he will give you a glider.
Use the glider you got from Leonardo da Vinci.
go on top of the rock near the cave then jump
Go to 1516 AD (4 o'clock on the time device) and return it to Leonardo Da Vinci. He will give you his Glider Wings.
The glider wings let you extend your jumps by slowing your rate of fall. They can be used to get the Peace Medal at 1516 AD and the (not required) Viking armor at 831 AD. (see related question)
There is no hang glider on the island.
First you need to get Leonardo's journal which is in the statue of liberty place. After you return it to him he will give you a prototype of a glider. Once you get that, go to the vikings and put the glider on. you should be able to get up there. P.S. You get a viking suit if you get to the cliff.
Except for "gliding" (glider wings on Time Tangled, balloons on Counterfeit), there is no way for your character to fly on other islands.
It is just a costume, on the island at 831 AD (2 o'clock on the time device). The only way to get it is to use the Glider Wings from Leonardo Da Vinci (4 o'clock 1516 AD).