Salamander: A Riddle

I found this cute little riddle in Salamander by Canadian author Thomas Wharton. It’s an old riddle of unknown origin, as far as I can tell. The novel is about a multi-century, world-wide search for the infinite book. It begins with the Slovakian Count Ostrov, who loses his son in the siege of Belgrade and retires to his ancestral castle to search for the hidden meaning of existence in the patterns of puzzles. Can you find the pattern in this one?

We are little airy Creatures
All of different Voice and Features;
One of us in Glass is set,
One of us you’ll find in Jet.
Another you may see in Tin,
And the fourth a Box within.
If the fifth you should pursue
It can never fly from you.