First in the Leviathan series.

Deryn Sharp--disguised as a boy so she can fly the floating airships and Alek Ferdinand--heir to the Austria-Hungarian throne, are both 15-year old but very new to the ways of the worlds they've been thrust into. Most of the story is from both their separate points of view until Deryn's ship crashes near Alek's hide-away in the mountains.
Once their stories intertwine the story gets more interesting as Deryn teases Alek about his irrational fears and disgusts over the conglomeration of living bodies that make up the Leviathan; Alek makes sure Deryn sees the advantage of machines. In between their banter is the truth of the situation: the survival of everything dear to them depends on teamwork; biotechnology is as necessary as gears, metalwork, and engines. Cooperation is the key to success.
Many interesting characters and since this is so obviously first in the series it will be interesting to see how everyone develops. It is an intriguing concept written in some historical truth but goes much further with a cyberpunk aspects. Looks like this will be a trilogy so looking forward to the rest of the books - maybe look for on CD.