It could be a wigeon you are describing.... the drakes do have a bit of a pintail-esque appearance to them.... when I was up and coming I often thought we had sprigs coming when we had wigeon (both are exciting anyway and both drakes in full plummage are true wall quality birds).

What I suspect you are seeing though is green wing teal.... to a new waterfowler... a wood duck in flight can often seem like a pintail... as the tail section is considerably longer and the wings set much farther forward than on other duck species. I remember thinking the same thing 15 years ago.... once you have seen some sprigs.... especially in a flock formation.... you'll be able to pick them out quick.... there really ain't no mistaking them..... and the noise they make is just awe-inspiring.

The reason also, that you haven't been seeing any green wing drakes is because they don't really look like drakes yet. The are still in eclipse plummage.... and while if you have one in hand or very close to you it isn't too tough to tell.... at a glance they all look the same.