Gnocchi - best fluffy technique
This post has been out there for a while - but I found that first parboiling the potatoes (about 10 minutes); then baking them, skins ON in a low-medium temperature oven, until cooked; then cooling slightly and scooping out the flesh; made for much fluffier and generally lighter gnocchi.  

Of course, you still need to mash the flesh well, but having it pre-cooked and almost dried out, means that mashing/handling the dough is minimised.  

As a bonus, you get to season and eat the delicious potato skins.