A riddle you don't have to be a genius to solve

Jonathan Swift (30 November 1667 – 19 October 1745) was an Irish satirist, essayist, political pamphleteer (first for the Whigs, then for the Tories), poet and cleric who became Dean of St. Patrick's Cathedral, Dublin. From Wikipedia:

I added one word in this riddle -- to make it a little easier (in my mind) to solve.  Good luck.  Don't give up too quickly.  I found it at the Futility Closet and you can click over there for the answer should you find it necessary.

A riddle by Jonathan Swift:

We are five little airy creatures,

All of different voice and features:

One of us in glass is set,

One of us you’ll find in jet,

T’other you may see in tin,

And the fourth a box within;

If the fifth you should pursue,

It can never fly from you.

What are we?