You might investigate using vital wheat gluten to enhance your dough. It's gluten extracted from wheat and milled into a fine powder. A little goes a long way, like a tablespoon per loaf of bread, and it can really pump up the protein content to help make an airy, chewy loaf of bread.

It really helps to lighten up rye and whole wheat breads, or breads using other grains like oats, which all tend to come out dense and heavy from a lack of gluten.

You could also try adding it to your high quality AP flour to bring the gluten content up to a normal bread flour level.