Preheat an air fryer to 360 degrees F (180 degrees C). Spray a nonstick 6x2-inch cake pan with cooking spray.

Combine sausage, eggs, cheese, bell pepper, green onion, and cayenne pepper in a large bowl; mix well to combine.

Pour egg mixture into the prepared cake pan.

Cook in the preheated air fryer until frittata is set, 18 to 20 minutes.