Welcome to the blog. If air bubbles are the problem, here is a trick I’ve heard about but never tried: After you grease and flour the pans, take some batter and smear it into the pans, as if you are frosting them on the inside. This will help to fill in the detailed areas. Then, continue to fill the pans as usual.
Sometimes, I spin my cake pans, or I slide them back and forth quickly across the countertop, to make the batter settle. I don’t like to tap them because I am afraid I will dent them by accident.
I also recommend that you try a bundt cake recipe. Bundt cakes are a type of butter cake, baked in a pan called a bundt pan, which has decorative detail.
I have a question. When you mix the batter, what kind of a mixing tool do you use? If you are using a whisk, you might be beating a lot of air into your batter without realizing it.