I promised I would not make anymore Riley Riddles...
...I failed to keep it.
Riddle me this:
My prefix and its prefix, are each an animal.
They fly, but one will only do it if impossible.
My suffix in a sandbag, will only make it lighter.
The food my prefix eats can be a prefix, too, for hire.
My suffix is a billion, and much older than you.
It's in my prefix, second half, but with N it is 2.
I have a principle and letters are superior.
My name has words of two, my first a prince by Warriner.
What am I?
This time, I tried to squeeze in as much information as I could, and I think this might prove to be an interesting one, unless you are tired of Riley Riddles (sorry @Level51).
The title is a clue.
The word has $10$ letters... but that's not the only hint.