Preheat an 8-quart air fryer to 390°F for 3 minutes. Pat thighs dry and unfold them, then rub with oil, salt, garlic powder and pepper.
Arrange in one layer with space between pieces and air fry for 8 minutes. Turn and cook for 6 to 8 minutes more until the thickest meat reaches at least 165°F.
Meanwhile, warm hot sauce, butter and vinegar in a small saucepan over low heat just until the butter melts; whisk smooth.
Brush the cooked chicken with half the Buffalo sauce and air fry for 1 to 2 minutes to set the coating.
Rest for 3 minutes, brush with the remaining warm sauce and serve.