First i roughly painted the landscape behind.

 

 

 

 

Quick sketch to make the pen drawing easier.

 

 

 

 

 All the big shapes of the planes are done using the pen tool, then blocked, ready to be refined.

 

 

 

 

Few proportions adjustements.

 

 

 

 

 

Rendering, the big part. Every part of the plane is done on a different layer.

 

 

 

 

 Refining the shadow.

 

 

 

 

Some more little adjustements, detail rendering.

 

 

 

 

 

Finally some few filters, a little blurry effect to cover my loose background.