When you have the crank, walk all the way back to the entry stairs and keep going forward. You'll find a ladder up to an area with an eagle and a crank-hole. Put your crank in the hole, and it'll sound a horn. Now the eagle will fly and scare all the birds away from your airship.

You go back to the airship, pull the lever, and it takes off. Your boss calls when you land, very upset with you. Great, doesn't anybody appreciate all the work you're doing??

Syberia Walkthrough, Tips and Techniques