I think I got it figured out, but only after looking at the pictures after the instructions. I think that the cut is between the goose units, but only the sky fabric is cut, not the interfacing. After the sky pieces are press up, then you would fold and sew horizontally to complete the strip of geese. |We are only seeing the tips here, not the original instructions.
This seems likely, it really helps to get all this input - its like the puzzle is starting to come together - the instructions are exactly as the tips on that web page - there are a few more pics - but they did not help me at all. I am thinking that it would be easier to do flying geese another way - I just wanted to try this and see - I will let you all know.