Need help making a model manifold/watertight (model attached)

Support Modeling
1

Greetings,
I have a model that I am trying to 3D print and Im getting an error that the parts are non-manifold/watertight. This model was made for me and I cant figure out how to fix it. I already tried to repair it in netfabb but still coming up non-manifold.
Im still learning Blender and looked over it and I cant see anything open, but I do have untrained eyes.

My 3d print program is showing that maybe there’s lines hovering over the model? maybe extra vertices or not connected somewhere.

If someone could look at it, that would be very helpful because I have a deadline fast approaching.

http://i.imgur.com/DrdYBtK.png
DrdYBtK.png1600×729

http://i.imgur.com/Pb0YPHl.png
Pb0YPHl.png1600×703
Wing1.blend (720 KB)

2

It is manifold but you have overlapping faces. In blender select your wing. In the modifiers tab (the wrench) in the subsurf, change view and render to both 2. Hit the apply button. Now tab into edit mode, hit a unti alll verts are orange, and then hit w (smooth) three times in a row. Export your obj or stl and it should work.