In a large bowl, toss together potatoes and onion with oil, salt, and pepper. Transfer mixture to air fryer basket. Air fry for 10 minutes or until potatoes are barely tender, shaking the basket halfway through cooking.
Add sausage to the air fryer basket and cook everything for 5 more minutes.
Combine Dijon mustard and honey in a small bowl.
Removed sausage and potatoes from the basket and put into a large bowl. Drizzle honey Dijon sauce over the sausage and potatoes and toss to combine.