Whipped egg whites in Gnocchi?
It's not traditional, but adding egg white is not unheard of, though in this example, it is not whipped.  There are recipes for gnocchi with whole egg, egg yolk only, and no egg as well.  It might contribute to fluffiness, but it also might throw off the consistency of the dough.  As you do some research on gnocchi, you will note several other variables that impact the consistency of the final product...type of potato and how it is treated, amount of flour, kneading/mixing time...egg or no egg.  It's certainly worth an experiment, and it is not unheard of for posters to do the legwork to answer their own question.  Try it out.  Let us know the result.