https://www.cnet.com/news/air-fryer-vs-convection-oven-which-one-should-you-choose/

Air fryers work by circulating hot air around your food. That's the same approach traditional convection ovens take, but there are a few key differences. 

While a full-size convection oven and an air fryer both use a fan to move hot air around, an air fryer circulates the air more rapidly inside a small chamber, speeding up the cooking process. Air fryers also employ a basket to more evenly circulate hot air around the bottom of your food.