I'd suggest going with a KML or GPX format to start with as this is more common for people and should be easier to implement.
Please also define the projection that is needed for it to work (or does it read PRJ files?).
I understand that it's experimental but at this stage it is putting the shape in the wrong spot (out by about 10 km) and is a strange infinity symbol shape rather than the simple square and other shapes I was testing.
Final suggestion is to load the shape/kml/gpx file into the viewer but then let the user click the flight plan around it manually (at this stage). Fully automated shp -> multiple separate flight plans (batch job style) based on name attribute and size of each polygon would be good vision to head for in the future.