Preheat the air fryer to 325°F by running it for 2-3 minutes before baking. Prepare the air fryer baking pan or basket by lining with a sheet of parchment paper. Set aside.
In a large bowl, whisk together melted butter, brown sugar, maple syrup, vanilla extract and egg yolks until smooth and uniform in color.
Add flour, baking soda and sea salt directly to the wet ingredients in the bowl. Use a spatula to mix until everything is just combined; do not over-mix. It will be soft at first but will stiffen as it sits.
Mix in chocolate chips (and any other add-ins) until they are well-distributed.
Using a small spring-loaded cookie scoop, scoop dough balls onto prepared pan or basket, leaving about 2 inches between each. (See notes about amount for each air fryer.)
Place the pan or basket in the air fryer. Set the air fryer to "Bake" and bake for 325°F for 7-9 minutes. (Times will vary depending on air fryer and how you like your cookies; see notes.)
When the air fryer is finished baking, remove the pan or basket from the air fryer and let the cookies remain on the parchment for about 5 minutes, allowing them to set and slightly harden as they will be soft and difficult to move when warm.
Use a spatula to remove cookies once set and let cool completely on a baking rack.