Cook the macaroni until al dente.
In a frying pan, cook the bacon until it begins to crisp. Add the garlic. Cook for 1 minute and add 3 tablespoons of the flour, stirring well until the flour and bacon fat take on a thick, pasty consistency. Slowly pour the milk and beer into the frying pan, whisking constantly for approximately 5 minutes or until the sauce thickens. Add salt and pepper, and stir in the cheddar and Parmesan until both cheeses have melted.
Place the cooked macaroni in a shallow baking dish and top with the cheese sauce. Stir until the macaroni is evenly coated, and place the dish in the refrigerator for approximately 45 minutes to let it cool and firm up.
Take a handful of macaroni and roll it into a large ball; repeat until all of the pasta has been used. Coat each macaroni ball with flour, egg wash, and then breadcrumbs.
Air fry the breaded macaroni balls until each one is nicely browned, about 10min. Serve while hot.