Random Riddle: 3-8-2013

A,E,I,O,U
Hold your mouse over for the answer.
We are very little creatures;
all of us have different features.
One of us in glass is set;
one of us you’ll find in jet.
Another you may see in tin,
and a fourth is boxed within.
If the fifth you should pursue,
it can never fly from you.

What are we?