Pound the meat. Lay the cube steak flat on a cutting board and cover it with plastic wrap. Use a meat mallet or a rolling pin to flatten each piece to an even thickness (about 1/3 inch).
Season. Season the cube steak on both sides with salt and pepper.
Set up your dredging station. Whisk the eggs and buttermilk together in a shallow bowl large enough to dip the steak into. Put the flour in another bowl and the breadcrumbs in yet another bowl. Line the bowls up in the following order: flour, egg mixture, breadcrumbs.
Preheat the air fryer. Preheat the air fryer to 425 degrees F.
Bread. Dip a piece of cube steak in the flour and flip to coat both sides. Next, dip it in the egg mixture, coating both sides. Finally, dip the cube steak in the breadcrumbs, coating both sides. Repeat with the remaining steaks.
Air fry. Arrange the breaded steak in a single layer in the basket of the preheated air fryer. Don’t crowd the air fryer. If you have to cook in batches, do so. Fry for 5 minutes on either side.
Make the gravy. While the steak is cooking, make the gravy. Melt the butter over medium heat in a saucepan. Once melted, whisk in the flour and cook until smooth and bubbling slightly. Whisk continuously. Slowly add the milk, ½ cup at a time, whisking continuously. Let the mixture simmer for a couple of minutes or until thickened to your liking. You can add more milk if you prefer a thinner gravy. Season with salt and pepper to taste.
Serve. Serve the cube steak warm, doused in gravy.