pretty blues
very smoothe work

.. love your use of line! My opinion ONLY,-- but I just may put a little teeny tint of red in the plane to match better (make it closer to the BG colour... or change it from blue completely)

The plane and bg are just not blending or contrasting enough... but hell i'd use it anyway
even if you just added some of that blue tint from the plane to the little polygons to enhance continuity throughout
9/10! =]]