The Iron Dragon's Daughter by Michael Swanwick.
An interesting take on the old idea of changelings. In this, a child is stolen away to the world of Faerie, and a changeling left behind. (the changeling is percieved by the parents as hopelessly retarded)
But Faerie is nothing like most fantasy versions. The world of Elves, Trolls, fanciful creatures and magic has evolved along with the human world, and is as high-tech as our own. Dragons are cybernetic "stealth fighters", with potent AI and magically-enhanced stealth technology.
The Elves, ruling all, have TV, shopping malls, and of course, warfare.
The principal, Jane, works as indentured labor in a dragon factory; until a dragon speaks to her.
This is my second read of this book, and it's as good the second time through.