Why does my WASC cake have an air bubbly internal texture. I am using the "original" recipe that calls for egg whites only and the oil. Are the whites taking in too much air ? Should I add whole eggs instead of just the whites? Or is it a mixing issue...too much mixing?? I don't mix it long nor on a high speed.

Hmmm. When I have lots of large air bubbles, it's usually from over mixing. If I know there are lots of bubbles in my batter, I drop the bowl or the filled pans on the counter a few times, and drag a skewer through the batter (like I'm marbling). HTH