In a bowl, combine the beef strips with soy sauce, Worcestershire sauce, brown sugar, garlic powder, onion powder, black pepper, and red pepper flakes. Mix well to ensure the beef is evenly coated.

Let the beef marinate in the refrigerator for at least 30 minutes, or up to 2 hours for maximum flavor.

Preheat your air fryer to 350°F (175°C).

Arrange the marinated beef strips in a single layer in the air fryer basket. Avoid overcrowding; work in batches if necessary.

Air fry for 10-12 minutes, flipping halfway through, until the beef is cooked through and reaches your desired level of dryness and crispiness.

Remove the beef jerky from the air fryer and let it cool completely on a wire rack. This allows the jerky to crisp further.

Once cooled, store the beef jerky in an airtight container in the refrigerator for up to a week or freeze for longer storage.